This course as the first one “Genetic Genealogy For Beginners” is an expansion and goes a little more deeper into the DNA with some additional learning tools. In these lessons rather than chapter we will use Genetic Genealogy, Molecular Genealogy (the field of biology that studies the structure and function at the molecular level and thus employs methods of both molecular biology and genetics. The study of chromosomes and genes expression of an organism.) Sounds intimidating but it will be broken into manageable understandable lessons. There is a test after each lessons to help you gain a solid background before moving to Intermediate and Advance Genetic Genealogy. This will be a four week course and starts May 1 – May 26 2017.
mark you calendar for this course.
BGA (Admixture) Explained
Source: BGA Admixture
BGA Basics And Science
BGA stands for biogeographical analysis. BGA tests are sometimes callAdmixture Tests. A BGA test basically tries to use your DNA to determine or pinpoint what part of the world your ancestor(s) originated. Using your DNA to show if two people have a common ancestor is valid. DNA contains information such as whether or not two people are related.
However using your DNA to pinpoint where an ancestor was born, lived, or came from, is entirely different. Here is the idea behind a BGA test.
Suppose we have a population called the Handy Clan. The Handy Clan has 1000 people and is located on a remote island. Now let’s say everyone in the Handy Clan population has a rare DNA marker which we will call -> M. In other words, thefrequency of this DNA marker is 100% because everyone (1000 people) has the DNA marker M. Also, let’s assume that no one outside of the Handy Clan, which is on this remote island, has the DNA marker M.
Now Laurie lives in the US in Oakland, California which is located outside the remote island and outside of the Handy Clan population. Let’s suppose we discover Laurie has this same rare DNA marker M.
Can we say Laurie is from or has ancestry from the Handy Clan population?
Under simple circumstances, yes!!! We can confidently say that. If no other population in the world has this rare genetic marker M, then we can say yes. Laurie is either from, or has had an ancestor, that originated from the Handy Clan population. That’s what a BGA does. It compares your DNA markers to a studied population. Since all one thousand people have the same DNA marker M, then Laurie must either have been born in that Handy Clan population or Laurie had an ancestor from that population.
However reality is not as simple as that!!!!! Let’s see a more realistic scenario.
A More Realistic Scenario
Now suppose we have three separate populations, the Handy Clan, Williams Clan, and Henderson Clan. Each population is located in a different part of the world. Each population or clan has 1000 people in it. Every person in each of the populations has the genetic marker M. In other words, the frequency of the DNA marker M is 100% in each population.
Now we discover again that Laurie, who lives in Oakland, which is outside each population, has the genetic marker M.
Question: Does Laurie has ancestry from the Handy Clan population?
Now things have changed. The question is now harder to answer. The fact that Laurie has a DNA marker M in multiple populations doesn’t necessarily mean Laurie has ancestry from the Handy Clan population. Laurie could of had an ancestor that lived or was born in any of those populations.
That’s the problem with a BGA DNA test. As we can see, the truth is not so clear cut in tests of this nature. The truth is based on a probability. Any newly introduced population can change things dramatically. Therefore, when interpreting the results from a BGA or Admixture test, please keep in mind that your results may differ or change tomorrow. Laurie would need a paper trail or some definitive piece of evidence to confirm the inference drawn from the BGA results. The BGA data numbers alone don’t necessarily prove anything.
The reason is that a BGA test is attempting to infer information from DNA that DNA doesn’t define. An ancestor’s original location can be any where. DNA simply doesn’t reflect or store that type of information. From the frequency (or concentration) of those DNA markers in each population, we are making an inference which could be right or wrong. If a child is born in say Atlanta, Georgia, that geographical location and information will not be stored in the child’s DNA.
One of the biggest misconceptions out there, is that a BGA or Admixture Test, can pinpoint the exact tribe or small population someone is from. As one can clearly see, this is not necessarily true. DNA alone simply cannot do this as it’s advertised. This is one of the reasons, the scientific community as a whole has not embraced BGA tests.
Now let’s look at the basic BGA concepts.
In BGA terms, the DNA marker M, is called an ancestry informative marker or AIM. Each population is called a reference population. An example of a reference population is the Yoruba. The Yoruba is a West African ethnic group that is studied by population geneticists. Many African-Americans have DNA markers that match to the Yoruba group.
Now that we have the BGA basics, let’s look at the BGA process and engine which is known as PCA.
BGA Process and PCA
The engine or workhorse of most BGA Analysis is PCA. PCA stands for Principal Component Analysis. PCA is a complex mathematical process that separates a bunch of data into its components. For example, let’s say we have a bag of 100 jelly beans that are of different colors. After separating the jelly beans by color, we see this -> blue=25, red=25, purple=25, and yellow=25. This means that each of the four colors make up 25% (25/100) of the jelly beans. PCA would essentially separate the jelly beans in the exact same way.
The BGA process starts off with about 300,000 AIMs or SNPs. These SNPs are found across the first 44 chromosomes in humans. The SNPs are matched to a number of reference populations. The results are percentages that represent theconcentration of the SNPs in each reference population. The engine running the show is PCA, which runs in the background of an algorithm.
Now let’s look at a few BGA tests.
BGA Tests: Population Finder, Ancestry Painting, McDonald
There are a number of BGA tests out there. Family Tree DNA’s BGA test is Population Finder. 23andME’s is called Ancestry Painting. The Population Finder is a BETA test so it’s a work in progress. Population Finder uses continental groups in addition to reference groups.
Here is an example of PF
Continent (Subcontinent) Population Percentage Margin of Error
Europe (Western European) French, Orcadian 28.53% ±0.48%
Africa (West African) Yoruba, Mandenka 71.47% ±0.48%
There are four reference populations -> French, Orcadian, Yoruba, Mandenka. This person basically has DNA markers that match those reference populations. It’s likely this person has ancestry from some of those populations, but not necessarily all of them. A paper trail would be needed to confirm ancestry.
Because the Population Finder is a beta test and has limited reference populations (same for 23andME’s Ancestry Painting), many people turn to an Extended BGA Analysis. This is where Dr Doug McDonald comes in.
McDonald’s Extended BGA
Dr Douglass McDonald is a chemist at University of Illinois in Urbana, Illinois. In fact, he actually created the Population Finder for Family Tree DNA. McDonald has access to more studied reference populations which Family Tree DNA or 23andMe currently doesn’t have. Because of this, you can get a more “fleshed” out or “extended” BGA Analysis.
McDonald gives his results in the form of an email with four graphs. Here are McDonald’s results of my cousin Lonette Lanier’s extended BGA test as shown in quotes below:
Most likely fit is 27.9% (+- 0.1%) Europe (various subcontinents) and 72.1% (+- 0.1%) Africa (all West African).
The following are possible population sets and their fractions, most likely at the top
French= 0.279 Mandenka= 0.721
Hungary= 0.280 Mandenka= 0.720
English= 0.277 Mandenka= 0.723
There is also about 0.4% Native American that is strong and likely real, as well as other little bits on the chromosomes but they are weak and probably unimportant.”
Each line, “French= 0.279 Mandenka= 0.721“, is a population set. There are three population sets. Each population set gives a likely or probable ancestry for my cousin Lonette. Each population set is a combination that gives the best fit for Lonette’s data. It doesn’t mean Lonette necessarily has ancestry from say, the French. But she does have DNA markers that match the French reference population. The multiple population sets are the result of Lonette’s DNA markers that are spread across multiple populations. This is why it’s difficult to pinpoint a person’s ancestral origin to a specific tribe or single population via your DNA alone.
It’s important to always backup DNA evidence with documents or other pieces of evidence to validate a claim. The numbers alone don’t always or neccesarily identify the truth.
Now let’s look at the issues the scientific community has with BGA Testing
Issues With BGA Or Admixture Testing
The scientific community as a whole hasn’t really embraced BGA or Admixture Testing. Using your DNA to establish whether two or people are related via a common ancestor is valid. However using your DNA to locate where your ancestor(s) originated is quite a different task. An ancestor could have been born or lived in any part of the world. More important – DNA simply doesn’t define or contain information such as ancestor’s geographical location or point of origin. That type of information is NOT an attribute of a genetic mutation. Therefore BGA or Admixture tests don’t have a basis in genetics. That’s the scientific community’s main objection to BGA or Admixture tests. The results from a BGA or Admixture test are used to make inferences from observed correlations. A correlation can be dangerous in science because it can lead to an incorrect inference from an observed set of data.
Finnish=.100 and Yoruba=.900.
This is based on the fact that the scientific community has studied the Yoruba and Finnish etc. This would lead one to believe that one has a large Yoruba ancestry. The Yoruba ancestry may be true with a paper trail.
Now suppose the scientific community has studied and approved a new reference population, C, in say a few years. Now a rerun of Dr McDonald’s results yields the following:
Population C=.450, Finnish=.100, and Yoruba=.450
Now as you can see, things have changed. My ancestor now could have lived in the Yoruba, or could have lived in the new reference population C. This scenario could happen. As you can see, none of these results are absolute or final in the sense that they can’t change.
In addition, different algorithms can produce different results. An algorithm is simply a method or set of steps to solve a problem. The algorithm is very important. It’s what produces your DNA results. Right now there are a number of tools out there that claim the ability to produce valid BGA results. Each of these tools may run under different algorithms.
For example – I have taken three BGA tests: Ancestry Painting, Population Finder, and McDonald. Each has produced different results. The analysis from 23andME stated I had 7 percent Asian ancestry. Now this could be significant or it could be noise. Neither FTDNA’s Population Finder nor McDonald’s findings gave 7% percent ancestry. The bigger question is which one is correct? Population Finder is a BETA test. So I can assume that it’s findings are approximate. Can the same be said for 23andME’s Ancestry Painting results or Dr McDonald’s BGA findings? The truth is that at this time – it’s impossible to tell which one is correct or is incorrect.
The most important point to take from this tutorial is that a BGA can yield valuable information not necessarily definitive information. Technically, the only factual based information that can be produced from a BGA test is that a person has DNA markers (AIMs) that match a reference population.
Genetic Genealogy for beginners was created to describe Genetic Genealogy in a simpler manner. Rather than a scientific approach to explaining genetic genealogy and the method and processes used in DNA testing, a clear and understandable nonscientific educational tool is offered to you in several chapter modules. Right now millions of people worldwide have purchased DNA test kits to explore their family ancestors and people have used perhaps several testing companies with different results and matches. The goal is to clear the fog and provide the tools required to understand genetic genealogy DNA testing. (Going forward I will be using the term DNA interchangeably with genetic genealogy).
There is a real need to educate and to continuously educate and help genealogists (anyone researching their family ancestry), to grasp and understand the beneficial attributes and limitations of DNA testing and methodologies. In this introduction and other chapters to follow, you will develop the tools to understand genetic genealogy (DNA).
After studying the chapters, you will be able to apply DNA specific vernacular and genetic genealogy evidence to explain genealogical questions. I will introduce types of DNA testing and how the test can be used for genealogy.
Genealogy (jene-ole-je) is a record or table of the descent of a person, family, or group from ancestor or ancestors; a family tree. It is the study or investigation of ancestry and family histories. (https://dictionary.com/browse/genealogy). Genetic Genealogy is the use of DNA testing in combination with traditional genealogical and historical records to infer relationships between individuals. (https://en.wikipedia/wiki/international_Society_of_Genetic_Genealogy) Both type requires meeting the genealogical and genetic genealogical standards if conclusions and evidence can be considered creditable and can be followed by others to reach the same conclusion and or expand upon to work presented. This is how genetic genealogy as any other science evolves over time. It becomes better and better.
Over time this material will change and the chapter modules will be adjusted overtime as new research and methods are introduced. I would recommend you subscribe to https://www.Africanamericangenealogydna.com) in order to receive updates to your chapter module materials.
Genetic Genealogy for Beginners Contents
See chapter 1, next
This blog was created to describe Genetic Genealogy in a more simple manner. Personally I have made discoveries about my personal family through the science of Genetic Genealogy. These new discoveries were made possible through the DNA Genealogical companies known as Family Tree DNA, 23andMe, GPS Origins (New), Helix (Geno 2) and AncestryDNA. The top five companies: MyHeritage Outstanding 9.8 rating, 23andMe Excellent 9.5, Living DNA Excellent 9.2 rating, Family Tree DNA Very Good 8.9 rating and GPS Very Good 8.7 rating. The science behind DNA Genealogy and how it can be of value in your family search using Genealogy tools is of a great value. Understanding the results can be overwhelming at first once you have your results.
Introduction To Genetic Genealogy
This is an introduction to DNA or Genetic Genealogy. This blog is written to clear the fog and confusion and to make things easier to comprehend. It is for beginners who have entered the Genealogical world and Genetic Genealogical world. As we you may already know, the concept of DNA is very popular and powerful. First lets understand that traits and features are passed from parents to children through DNA. We hear about DNA in the news, in paternity tests, exonerating falsely accused people, revealing human origins, etc. It shouldn’t come as any surprise that DNA has now made it into the genealogy arena. Basic Concepts There are two basic concepts that form the foundation of Genetic Genealogy. A)When two or more living things share segments of DNA, there is or was a shared common ancestor that lived in the past that connects those living things. For example, if you compare your DNA to your 1st cousin’s DNA, then some of your DNA is going to be similar to your 1st cousin’s DNA. This is because you and your 1st cousin have the same grandparents. The grandparents are the common ancestors. Each grandparent passed a percentage of his or her DNA all the way down to the 1st cousins.B)The more DNA you share with someone, the more closer you are to that person.This means that your last common ancestor lived in a more recent time frame. For example, a brother and sister are more closer to each other, than either one of them are to their cousin. The last common ancestor shared between siblings are their parents, where as the last common ancestor shared by 1st cousins are their grandparents. Siblings share on average, 30 to 50 percent of their DNA with each other. Cousins share 12.5 percent of their DNA with each other.
Average percent DNA shared between relatives
To help in interpreting your DNA relatives results, the following summarizes the average percent DNA shared for different types of relationships according to 23andMe. Note that several relationships share the same average percent DNA.
Identical Twins average 100% DNA shared
Parent/Child Full Sibling average 50% (50% from each parent) Varies by specific relationship
Grandparents/Grandchild, Aunt/Uncle, Niece/ Nephew, Half Sibling average 25%, Varies by specific relationships
1st Cousin Average 12.5% (range 7.31% – 13.8%)
1st Cousin once removed Average 6.25% (range 3.3% – 8.51%)
2nd Cousin Average 3.13% (range 2.85% – 5.04%)
2nd Cousin once removed Average 1.5% (range 0.57% – 2.54%)
3rd Cousin Average 0.78% (range 0.3% – 2.0%)
4th Cousin Average 0.20% (range 0.07% – 0.05%)
5th Cousin 0.05% (range variable)
6th Cousin average (0.01% range variable)
Source: 23andMe 2017 and Gliesians, LLC Data Science Services, 2017
A recent DNA discovery placed our relationship at 0.17% a range of 0.07% – 0.05%. Looking at the chart above we are within the 4th to 5th cousin range. Hopefully you can share surnames in order to make the connection.
When you get your DNA results, what the results mean depends on what type of DNA test you submitted.
Types Of DNA Tests
There are three basic types of DNA tests on the market:
2. Autosomal DNA Test – Humans have 46 chromosomes. The first 44 chromosomes are called the autosomes. An autosomal DNA test identifies shared segments of DNA across the first 44 chromosomes When you and another person share a significant amount of DNA segments across your autosomal chromosomes, then you and that person have a common ancestor in your respective pasts. It is from that ancestor that you and your match received the shared DNA segments. The DNA amount, size, and segment length is represented as a unit of measurement known as the centiMorgan (cM). An autosomal DNA test uncovers and reveals relatives (matches) on both sides of your family in a genealogical time frame. There are two major limitations that are associated with an autosomal DNA test. The first limitation with an autosomal DNA test is that it cannot identify which side of your family a match is on. This is due to the fact, that it’s impossible to know which chromosome you received from which parent. Of the 44 chromosomes analyzed by the test, 22 of the chromosomes you received from your mother, and the other 22 you received from your father. In order to know, you must test a parent, grandparent, or another ancestor or relative. If that ancestor or relative matched to the same person that you matched to, then you know which side of your family your match is on. The second limitation is that an autosomal DNA test can only go back 6 to 7 generations (last 200 to 300 hundred years). This is due to a natural process known as recombination which will be discussed in a separate blog. An autosomal DNA test can identify parents, cousins, aunts/uncles, siblings, distant cousins, etc. An autosomal DNA test can also identify half relatives as well. 23andMe’s autosomal DNA test is called DNA Relatives. Family Tree DNA’s autosomal DNA test is called Family Finder. Ancestry.com’s autosomal DNA test is called AncestryDNA. 2)Y- DNA Test – In humans, chromosome numbers 45 and 46 are the sex chromosomes.
3. Y-DNA Test-Women have two XX chromosomes. A male has an X and Y chromosome. A Y-DNA test is strictly for men. The 46th chromosome in men is the Y- chromosome. As before, when two men share an identical amount of DNA on their Y-chromosomes, then those two men have a shared paternal (male) common ancestor. The Y-chromosome’s inheritance is son -> father -> father’s dad -> father’s dad’s dad, etc. Because your last name or surname (Montgomery, Johns, etc) is inherited in a similar fashion, a Y- DNA test can be used to see if a group of say, male Montgomery’s, are related. Given the fact that some surnames are fairly common (for example Montgomery, Johns, Myatt, Rand, Boothe, etc), a Y-DNA test can help tremendously. On the other hand, a Y-DNA test can go back hundreds to thousands of generations in the past. This is due to the fact that the effects of DNA recombination are absent from a Y- DNA test. However, a Y- DNA test is mainly used for recent ancestry (last 200 to 300 years). In addition, a Y-DNA test gives you matches AND a Y-DNA haplogroup. (Haplogroups are explained in a separate blog.) Family Tree offers a Y-DNA test. Neither Ancestry.com nor 23andME offers a Y-DNA test. However both 23andMe and Ancestry.com do assign you a Y-DNA haplogroup. (For example E1B1A7A is aY-DNA haplogroup) My Y-DNA haplogroup is E-P252.3).
4. mtDNA Test – Inside a human cell, there is a structure called the mitochondria. is the battery of the cell. There are multiple copies of the mitochondria inside a single human cell. Inside a single mitochondria is a round circular piece of DNA called the mtDNA. The important thing to understand is that only women pass along their mtDNA to their children. A human male does not pass along his mtDNA to his children.Therefore, the inheritance of the mtDNA is child -> mother -> mother’s mom -> mother’smom’s mom -> etc. The same principle applies as already mentioned. When you and a person share an identical amount of DNA on your respective mtDNA’s, then you and that person have a common maternal ancestor. The mtDNA changes very slowly. Because of this, the mtDNA is mainly used for deep distant ancestry. In other words, the last common maternal mtDNA ancestor that’s shared between two or more people, may have lived thousands of years ago. Unless your entire mtDNA is identical to someone else, then you and that person are very likely distantly related. The effects of DNA recombination are absent from a mtDNA test. This allows a mtDNA test to go back and span many generations (years) in the past. A mtDNA test gives you matches AND a mtDNA haplogroup. (Haplogroups are explained in a separate document.) Family Tree DNA offers a mtDNA test. Neither 23andME nor Ancestry.com offers a mtDNA test. However, 23andMe and Ancestry.com both do assign you a mtDNA haplogroup. (For example, L3c2a is a mtDNA haplogroup). My mtDNA haplogroup is L2a1a2.
5)BGA (Admixture) DNA Test – There is a 4th separate DNA test called a BGA orAdmixture DNA Test. BGA stands for biogeographical analysis. A BGA test attempts to useyour DNA to identify what part of the world your ancestors originated from. If your DNA testresults have something like – 69% African, 21% European, and 10% Asia, then you had aBGA test performed on your autosomal chromosomes. BGA Tests are controverisal. Currently the accuracy and validity of such tests are questioned and generally not accepted by the scientific community. Therefore you should accept BGA tests with a grain of salt. Such tests are not conclusive and can change with the introduction of new data. In addition, the results of such BGA tests can vary between different DNA testing companies. This is mainly due to the use of different algorithms and testing methods used by each company. The same holds true for any online 3rd party tool such as Gedmatch, Dodecad Ancestry Project, etc that claims to produce BGA results. BGA
tests will be fully explained in a separate blog. BGA is constantly changing as algorithms and methods change and happen everyday. Testing standards are being develop to clear the fog and give consumers a better understanding of what they are getting from testing companies. Example: I ask one company about their database and how they went about developing their biographical analysis. Answer we are completing Europe and moving to other countries. African is not on their radar at all, but yet they do explain that in their literature. Summary: In short, a Y-DNA test looks at only one side of your family (father’s strict paternal side). A mtDNA test looks at only one side of your family (mother’s strict maternal side). An autosomal DNA test looks at both sides of your family (both meaning everything. For example your dad’s mom side or your mom’s dad side. This can include the father’s strict paternal side or the mother’s strict maternal side as well).
Suggested reading material and resources used in this blog.
Blaine T. Bettinger, “The Family Tree Guide to DNA Testing and Genetic Genealogy”•Emily D. Aulicino, “Genetic Genealogy The Basics and Beyond”•Megan Smolenyak Smolenyak and Ann Turner, “trace Your Roots with DNA” and The National Institute of Health “Genome Project”
Any questions, please subscribe to AfricanAmericangenealogydna.com or email me a email@example.com
Written by Ellen Hinkley
3 February 2017
Source: DNA Testing Choice@DNATestingChce (The UK’s leading news and reviews site for the DNA Test you can buy online) access 2/7/2017
When it comes to DNA testing to explore your genetic heritage, there are three main types of test that you can take: Genetic ancestry tests, genetic predisposition tests and trait tests.
Ancestry tests can report on your ethnic mix and allow you to trace your ancestry back hundreds of thousands of years. There are three main types of genetic ancestry test: Y-DNA tests, mitochondrial DNA (mtDNA) tests and autosomal DNA tests.
Genetic predisposition tests can be used to identify any medical conditions that you might be predisposed to suffer with later in life. Trait tests can report on the physical or psychological attributes you’ve inherited. For example, you may discover that you’re predisposed to anger quickly, and that your short temper is part of your genetic heritage!
If you’d like to explore your DNA heritage with an ancestry test, we’ve listed the companies that provide genetic ancestry testing. If you’re more interested in understanding how your genetic heritage could affect your health, then check out the companies selling genetic predisposition tests such as Veritas Genetics. If you’re wondering about the traits that you’ve inherited, our personality testing listings are a good place to start!
Genetic ancestry tests
Y DNA tests
Y DNA tests analyse the Y chromosome which is passed down from father to son – for this reason, only males can take this type of test. Y DNA tests allow you to trace your paternal line (your father’s father’s father etc.) by revealing your paternal ‘haplogroup’ – a code used to describe the individuals with whom you share a common paternal ancestor. Your paternal haplogroup can be used to reveal the migratory path that your paternal ancestors took after leaving Africa 100,000-200,000 years ago. Some Y DNA tests will also allow you to find living relatives on your paternal line, to help you undertake DNA genealogy. You can find out more about tracing your paternal heritage with a Y DNA test in our article: What is a Y DNA test?
Mitochondrial DNA tests
Mitochondrial DNA testing provides similar information to Y DNA testing, but instead analyses the DNA that you inherit exclusively from your mother. Mitochondrial DNA is passed down from mother to child, regardless of gender, so anyone can take this type of test. Similarly to Y DNA tests, mitochondrial DNA tests will provide you with your maternal haplogroup, allowing you to explore your maternal genetic heritage going back several hundred thousand years. Some mitochondrial DNA tests are also genealogical DNA tests, helping you to find living relatives on your maternal line. You can read more about mitochondrial DNA testing in our article: What is a mitochondrial DNA test?
Autosomal DNA tests
Autosomal DNA testing allows you to explore your more recent genetic heritage (the last five to six generations of your family), by analyzing 22 of the 23 pairs of chromosomes that you inherit from your parents (your autosomes). Because your autosomes recombine shortly after you’re conceived, it’s not possible to identify which autosomal segments you’ve inherited from which parent, so these tests give you a combined view of your genetic heritage from both parents.
Autosomal DNA tests (sometimes known as ethnicity tests) will reveal the ethnic groups who’ve contributed to your DNA, and some tests double as genealogy DNA tests, allowing you to find living relatives with whom you share segments of your autosomal DNA. You can read more about autosomal DNA testing in our article: What is an autosomal DNA test?
Genetic Predisposition testing
Another method of exploring your DNA heritage by taking a genetic predisposition test – these allow you to assess your genetic risk of developing medical conditions, from cancers and chronic diseases, to allergies, intolerances, and ailments like back pain. There are a number of private companies that offer genetic predisposition testing in our health section, so you can see what the likes of Veritas Genetics offer.
One well publicized example of a condition that you can be genetically predisposed to is breast cancer. Although anyone can suffer with breast cancer at some point in their lives (even men), the level of risk varies from person to person. If you were to inherit certain genetic variants in the ‘BRCA’ genes from your parents, your risk could be significantly higher than average.
Fortunately, a genetic predisposition test can reveal the presence of these ‘problem variants’, and help you prepare for the future. In 2013, actress Angelina Jolie revealed that she had undergone a mastectomy in response to the results of such a test. Since then, the number of people using genetic predisposition tests to screen for problem variants in the ‘BRCA1’ and ‘BRCA2’ genes has increased by nearly 40%.
Something worth pointing out is that testing for problem variants in the BRCA genes is a rare example of a genetic test that you can potentially get for free. If one of your close relatives has already tested positive for these variants, or you have a history of breast cancer in the family, you may be eligible for a genetic predisposition test on the NHS. If this is something you’re keen to explore, we recommend that you discuss your options with your doctor.
Something worth pointing out is that several health insurance companies now cover part of the cost of testing for genetic variants in the BRCA genes, providing you have a strong familial link to the disease. If you’re interested in a genetic predisposition test and you think you might be eligible for this type of coverage, it’s worth getting in touch with your health insurance provider before purchasing. If your insurance doesn’t cover the cost, or you don’t have health insurance, there are other ways of reducing the price of the test, and you should discuss your options with your physician.
What does the term ‘genetic predisposition’ actually mean?
There are a few things that you should be aware of if you’re considering a genetic predisposition test. Firstly, it’s important to understand that in most cases, carrying a genetic variant that’s associated to a medical condition doesn’t necessarily mean that you will go on to develop it. The results you receive will show how much more or less likely than average you are to suffer with the condition, according to the current published research.
If you’re facing an increased risk, the company conducting the test will normally tell you what you can do to reduce these risks. On the other hand, if your test reveals that you’re facing a decreased risk, it’s worth bearing in mind that this doesn’t mean you’re immune to the condition.
Once you’ve identified your ‘genetic risk’ of suffering with a medical condition, you should bear in mind that this is not the whole story. For the vast majority of conditions, many non-genetic factors can affect your risk e.g. your diet, your weight, whether you’re a smoker.
If you’re considering a genetic predisposition test for an incurable condition such as Alzheimer’s disease or Parkinson’s disease, it’s important to think carefully about the repercussions of discovering you have an increased risk. Many people who’ve seen elderly relatives suffer with such conditions have wanted to know if an increased risk is part of their DNA heritage, whilst many others would prefer not know. There are many benefits to identifying a heightened risk to an incurable condition – you may wish to try new treatments to mitigate its onset, plan your retirement differently, or sign up for trials in order to help seek a cure. On the other hand, if you discover you have a heightened risk, it’s not possible to ‘unknow’ this information, and you may be better off not knowing than learning about something that’ll cause you stress and anxiety.
If you purchase a genetic predisposition test through your medical professional, you’ll normally receive genetic counseling both before and after you take the test. This will allow you to learn about the potential outcomes of the test and ask any questions beforehand. Once the results are in, you’ll have the support you need to explore your options moving forward.
If you purchase a genetic predisposition test through a private company, make sure you check their website to see if genetic counseling is part of the service. Though many company websites will explain the test, its limitations and the potential outcomes, for serious medical conditions, we’d strongly recommend you buy from a company that offers ‘face to face’ or phone support, once you receive your results.
As well as testing for your own predisposition to medical conditions, you may wish to undertake ‘carrier screening’ to assess the risk of your passing on conditions to your children. One of the most common types of carrier screening is for cystic fibrosis, a condition which is caused by a genetic variant in the ‘CFTR’ gene. You may discover that although your partner and yourself do not suffer with a medical condition, you may both carry a problem genetic variant that means there’s a chance that your children will develop one. If this turns out to be the case, there are measures you can take, such as IVF with preimplantation genetic diagnosis, to reduce the chances of your child inheriting the condition.
It’s worth noting that many genetic ancestry companies will let you download your digitized genetic data after you take their test: 23andMe, Family Tree DNA and Ancestry.com are three such companies. By downloading your ‘raw data’ (a zipped file that’s normally under 20 MB) you’ll be able to upload it to a number of third parties that can re-analyse it for free or for a small fee. This will often reveal additional information about your ancestral heritage, or potentially identify new genetic variants that are associated to an increased risk of suffering with a medical condition.
Tests for your genetic heritage aren’t limited to those that uncover your ancestry or establish your risk of suffering with (or carrying) a medical condition, they can also be used to reveal the physical and psychological traits that you’ve inherited.
The most popular trait tests are those that can provide training or nutritional plans that are tailored to your DNA, to help you achieve your fitness goals. This type of testing is possible because a number of the genetic variants that you’ve inherited are linked to how effectively you respond to certain types of exercise, your predisposition to injury, and your metabolism. If these types of test are of interest, then check out the companies selling fitness and diet DNA tests such as Fitness Genes and DNAFit.
Other tests for inherited traits will report on your caffeine metabolism, earwax type, hair curl, and all sorts of other physical characteristics that make up your genetic heritage. Many of the traits you can test for may be interesting but won’t impact your life whatsoever. On the other hand, if you’re concerned about male pattern baldness and you wish to test for this trait, taking a test may allay your fears or encourage you to seek treatment options while you still can!
There are also genetic tests for your personality traits which can reveal the characteristics that are part of your genetic heritage (nature) vs. those arising from your upbringing (nurture). Genetic personality tests are relatively new, but the studies supporting the associations between genetic variants and aspects of your character are growing in number. You can test for traits such as confidence, spontaneity, optimism, sex drive, aggression, and many many more! Some of these tests will also include a personality quiz to take non-genetic factors into account, to give you a more accurate picture of the psychological forces at work.
After many hours and days exploring the literature on DNA testing and the pros and cons to testing, not to test, what to test for, what companies are best to meet your needs, all the testing possibilities, procedures, logarithms used by each company, results in simple terms you can understand, were to place your raw data after the test and what companies will secure your information it seemed appropriate to blog this to you.
Many African-Americans and others are using an African DNA test to get answers about their ethnic ancestry.
Typical questions include the following:
Fortunately, there are several reasonably priced African DNA tests that answer these and other questions about one’s ethnic ancestry.
The tests all use home test kits and sample collection is easy and painless. Depending on which company you use, you might wipe some cells from inside your cheek with a little swab or spit some saliva into a tube. No blood is required.
Here are my top seven recommendations for anyone interested in an African DNA test.
1. Ancestry DNA
AncestryDNA (http://www.ancestry.com) recently rose to the top of this list. Both men and women can take the test and it will identify other people in the database who share common ancestors with you. It is an autosomal test similar in technology to Family Finder (http://www.ftdna.com) and 23andMe (http://www.23andMe.com), discussed below.
The test includes an Ethnicity Estimate that summarizes the percentage contributions of different regions of the world to your overall ancestry. That estimate now breaks African Ancestry into nine regions:
This is the first widely recognized, legitimate DNA test to provide this detailed a breakdown of African ancestry
2. Family Finder, which includes Population Finder
Family Finder is an autosomal DNA test from Family Tree DNA. It’s widely used by genealogists, including those interested in African American genealogy.
The company will compare your DNA against a database of other users to find genetic matches. Most often these genetic matches will be cousins, having a common ancestor with you somewhere in the last five or so generations.
By emailing your matches you can connect with previously unknown relatives and learn much more about your family tree.
As part of the Family Finder test, you receive a myOrigins report, formerly called Population Finder, where the company compares your DNA with over 60 reference populations from around the world. This is a biogeographical analysis of the DNA you received from ALL of your ancestors.
The African part of your DNA may place you in any of four sub continental groups based on similarities to certain scientifically studied populations. The groups and populations are as follows:
Very few people outside Africa are 100% African. Population Finder will classify the remaining portion of your ancestry using other populations.
3. Y-DNA Test at Family Tree DNA
Family Tree DNA also offers a Y-DNA test, which tracks your paternal line. Since only men have a Y-chromosome, only men can take this test. But women can still test a man from their paternal line, e.g. a brother, a father, a brother of your father, or a son of your father’s brother.
Like Family Finder, this test finds genetic matches who share a common ancestor. But with the Y-DNA test you know the common ancestor has to be a male in the direct paternal line like your father’s father’s father etc.
The Y-DNA test will also predict a man’s Y-DNA haplogroup. And many haplogroups are clearly tied to origins in sub-Saharan Africa. This is the real indicator of your paternal line’s ethnic ancestry.
TIP: If you’re interested in finding genetic matches, you should order the Y-DNA 37 test, which checks 37 markers. But if you’re only interested in determining your haplogroup, you only need 12 markers. I suggest you go to Family Tree DNA and look for the combination package of Family Finder plus Y-DNA 12. The combo price is an excellent buy.
If you later decide that you want to discover your precise position in the Y-DNA tree of life, you can upgrade to more markers or even order a Deep Clade test. That will tell you exactly which subclade of your haplogroup you’re in. In many cases this can tighten the geographic origins of your paternal line.
4. mtDNA Test at Family Tree DNA
Both men and women have mitochondrial DNA (mtDNA) to test. But only women pass it on to their children. So mtDNA is the test to track your maternal line. That’s your mother’s mother’s mother etc.
As with the test described previously, you will probably see matches with other users. But mtDNA mutates so slowly that your common ancestors may have lived thousands of years ago. That makes mtDNA less useful than Y-DNA as a genealogy tool.
Still, mtDNA also has a haplogroup that relates directly to the origins of your maternal line. And some of those are clear indicators of African origin.
5. 23andMe Which Includes Ancestry Composition
23andMe is another autosomal DNA test like Family Finder. This test can also serve as an African DNA test, because it has an Ancestry Composition feature that tells you what parts of the world your ancestors lived a few hundred years ago.
This admixture report is similar to the Population Finder feature of the Family Finder test. It reports on African Ancestry from these three regions:
However, if you also test at least one of your parents on 23andMe, this test can split your ancestral percentages into your paternal and maternal sides.
23andMe also has a DNA Relatives feature that’s similar to Family Finder and it will estimate your Y-DNA and mtDNA haplogroups. So if you want to cover all your bases—then the 23andMe test can be a great value as an African DNA test.
Harvard University Professor Henry Louis Gates, Jr. was a pioneer in African DNA testing. He founded African DNA to encourage more African-Americans to get their DNA tested.
The company offers a Y-DNA test of 25 markers and an mtDNA test like the mtDNA Plus test at Family Tree DNA. In fact, Family Tree DNA is affiliated with the company and does their DNA testing.
Now they can also offer the Family Finder test that they renamed Ancestry Finder.
Note that African DNA only offers one paternal line Y-DNA test and one maternal line mtDNA test. They do not offer additional Y-DNA markers, the Full Mitochondrial Sequence (FMS) test, or Deep Clade testing. You need to order those tests directly from Family Tree DNA.
The African DNA web site does have more content specific to African DNA testing than any of the more general DNA testing companies. So I encourage anyone looking for an African DNA test to visit the site and learn all you can.
Uniquely, African DNA does offer some higher priced packages that combine DNA testing with genealogy research to build your family tree.
For most African-Americans there are no genealogical records prior to the 1870 census, when last names of former slaves began to be recorded. If you want someone to build a few generations of your family tree, however, this is an option to consider.
MONEY-SAVING TIP: If you’re not ordering a package with genealogy research, be sure to recheck Family Tree DNA to compare prices before placing an order with African DNA. At the time of this writing, you can order the same Y-DNA and mtDNA tests directly through Family Tree DNA for significantly less money.
7. Y-DNA and mtDNA Testing at African Ancestry
African Ancestry is another company that specifically features African DNA tests. Like the companies above, they check your Y-DNA and mtDNA to determine your paternal and maternal lineages. Since their web site does not provide details of either test, I cannot compare them.
Unlike Family Tree DNA, they do not keep a database of customer results, so you will not receive any matches to people with similar DNA. Since the company does not have an autosomal test like Family Finder and 23andMe, it cannot provide any admixture percentages. You won’t learn anything about ancestors outside your narrow paternal and maternal lines.
I found some interesting data on the web site. Even though this site specifically attracts people of African descent, 35% of the paternal line tests show European ancestry. Much of that non-African DNA was introduced into the family tree during the era of slavery. In addition, 8% of their maternal line samples show non-African haplogroups.
An article in the Wall Street Journal was critical of the African DNA test reports provided by this company. Independent experts say that mitochondrial DNA is not sufficient to nail down an ancestor’s origin to a specific country.
Furthermore, the large migrations of Africans over the last 3,000 years means that the typical black American’s DNA will match Africans living today in several countries. Even the founder of African DNA was quoted in the article that the country-specific reports his company provides are largely a “best guess.”
The testing prices at African DNA are higher than those of the companies listed above. Even if you have your African DNA test done elsewhere, the African Ancestry web site includes some interesting information on African heritage and a list of country-by-country resources in Africa for genealogists.
Other African DNA Tests of Uncertain Quality
DNA Tribes uses autosomal markers representing all your ancestors. But unlike AncestryDNA, Family Finder and 23andMe, which check nearly a million autosomal SNPs, DNA Tribes checks a maximum of 27 STRs.
I won’t try to explain the difference between an STR and a SNP h//ere. But autosomal STRs are what police forces around the world have been collecting from criminals for decades.
The company examined 383,000 STR records and claims to have identified major genetic regions around the world. They compare your DNA with their proprietary database and issue reports on your most closely matched regions.
The company does not share its database or reveal its methods. And independent experts are skeptical when such detailed reports arise from so few markers.
Roots for Real offers Y-DNA, mtDNA, and an autosomal test based on 16 STR markers. They position their autosomal admixture test as an African DNA test. But their database is only about one third the size of the already questionable DNA Tribes test. And all of their tests are overpriced compared to market leaders Family Tree DNA, 23andMe, and Ancestry.com.
Warning: These tests are based on sound science. But if you don’t know exactly what you’re doing, you can take the wrong test for your situation. It’s also easy to pay too much…settle for incomplete data…or misinterpret the results.
Y-DNA 111 markers, mtDNA + Plus, Full Sequence DNA and Family Finder DNA
My Haplogroup: Y-DNA (E-M2) and mtDNA (L2a1a2
http://www.23andme.com/DNA assess 2/10/2017
http://www.ancestry.com/DNA assess 2/10/2017
http://www.myheritage.com/DNA assess 2/12/2017
http://www.africanancestry.com/home/ assess 2/04/2017
https://www.africandna.com/ assess 2/04/2017
Megan Smolenyak Smolenyak and Ann Turner, “Trace Your Roots with DNA” published 2004
Blaine Bettinger, “The Family Tree Guide to DNA Testing and Genetic Genealogy” published 2016