Genetic Inheritance Follows Rules Concept 5

 

Ref: DNA for beginners.org, access Aug 1, 2017

When Mendel proposed that each trait is determined by a pair of genes, it presented a potential problem. If parents pass on both copies of a gene pair, then offspring would end up with four genes for each trait. Mendel deduced that sex cells — sperm and eggs — contain only one parental gene of each pair. The half-sets of genes contributed by sperm and egg restore a whole set of genes in the offspring.

Mendel found that different gene combinations from the parents resulted in specific ratios of dominant-to-recessive traits. The results of a cross between two hybrid parents — each carrying one dominant and one recessive gene — were key to his synthesis. For example, a cross between two yellow-seed hybrids produces three times as many yellow seeds as green seeds. This is Mendel’s famous 3 to 1 ratio.

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Genes Don’t Blend Concept 3

 

 

Ref: DNA from the Beginning.org

In general, offspring appear to be a mixture of parental characteristics. However, Mendel found that this is not true for the pea plant traits that he chose to study. Pure-bred pea plants when crossed did not produce offspring with blended traits.

For example, one might expect that a cross between pure-bred green-seeded and pure-bred yellow-seeded pea plants to produce offspring with seeds of an intermediate green-yellow color. After all, color blending happens when paint is mixed together. However, Mendel found that this cross produced offspring with only one color — yellow. No intermediate blends were seen, and the green color seemed to have disappeared.

Help Drive Research Forward for African Americans

23andMe Post

We believe genetics and the study of disease should be for everyone.
All ethnicities. All people.

Help drive research forward for African Americans.

Join now!

Questions: contact study-help@23andMe.com

Why your help is so important.

Less than 5% of research on the genetics of disease includes people of African ancestry. If people with diverse ancestries continue to be underrepresented in genetics research, then we risk missing key medical and other scientific discoveries that could benefit everyone.

If you participate in the African American Sequencing Project, you could help address this disparity. By sharing your genetic data with the scientific community, you can shape the future of genetics research to include people of African descent.

Only a fraction of genetic research studies have included people of African descent.

Popejoy, A. B. & Fullerton, S. M. Nature 538, 161-164 (2016).

See if you’re eligible

To be eligible for this study you must be a 23andMe customer, have consented to 23andMe Research, self identify as African or African American and be at least 18 years old.

How it works

You do not need to provide a new saliva sample — we will use the one you already sent us.

There is no cost to participate.

You consent to share your genetic data.

Enroll and agree to share your de-identified genetic information with researchers approved by the National Institutes of Health (NIH) and qualified research partners of 23andMe.

None of your contact information or answers to 23andMe surveys will be shared.

We will sequence your genome.

If you are selected, we will send your saliva sample, already provided to 23andMe, to a lab for whole genome sequencing. Whole genome sequencing is a more thorough but also more costly review of your genome than that provided by the genotyping analysis used to generate your 23andMe reports. *This is extremely important. The real cost to an individual is about $1200 with most labs. Entire genome sequencing means all of your DNA in your body. I am a member of the Ethnicity Research Group studying and identify the location specific location of African and African-American ancestors and I also participate in the L2 study group, this later group requires identification with a person of African origin. right now these two groups are closed.

For more information on sequencing versus genotyping watch this video or read this article.

We will provide data to researchers around the world.

23andMe will share this sequenced genetic data with researchers by depositing it into a scientific database approved by the NIH. Approved researchers will have access to this data to conduct genetics research.

About this project

In October 2016, 23andMe was awarded a grant by the National Human Genome Research Institute, a major research arm of the National Institutes of Health, to fund the African American Sequencing Project.

This project is part of our broad commitment to diversity in genetics research. Learn more about 23andMe’s Roots into the Future Project.

Privacy and Security

We do not share your genetic information without your explicit authorization. Only you can decide if you would like to participate in this project by authorizing 23andMe to share your information with outside researchers.

Even though you previously consented to participate in 23andMe Research, you will need to read and accept additional consents to participate in this study.

Hi. Have additional questions about the African American Sequencing Project?

If you don’t see your question here, get in touch with us.

  • What does it mean to be a research participant in this project?

  • Why is 23andMe conducting the African American Sequencing Project?

  • Will you share my genetic data with third parties?

  • Do I need to provide a new saliva sample to 23andMe?

  • How will you protect the confidentiality of my data?

  • What is whole genome sequencing? How is this process different from genotyping, the process previously used by 23andMe to analyze the DNA in my saliva sample?

  • How do you select participants for this study?

  • Will I have access to my sequenced data?

  • What am I agreeing to if I accept the consent documents for this project?

Myth About DNA Test

Myth: A DNA test can pinpoint precisely where
your ancestors lived or which tribe they belonged to.
If your ancestors and their offspring had stayed in one geographic
region and never allowed outsiders to enter, it would be relatively
easy to distinguish their DNA (and yours) from the DNA of
people living in other regions. Over time, all of the inhabitants of
your region would come to share specific genetic mutations (usually
harmless changes in DNA), which would identify them as a
distinct population, the same way a surname identifies members
of a family.
But our ancestors didn’t stay in one place. For thousands of
years, humans have moved about, leaving their genetic imprints
wherever they procreate and making it increasingly difficult for
geneticists to distinguish one region’s population from another’s.
Scientists can make inferences about your ancestry based on
trends among populations, but they can’t say for sure that your
ancestors lived in a specific country, much less a specific town.
Testing companies analyze a person’s genetic makeup by comparing
his or her DNA to a reference database of DNA samples
from modern individuals living in various regions—such as residents
of present-day African countries. But it’s important to keep
in mind that today’s inhabitants of a given region are genetically
different from the people who lived there before migration
occurred. Just because your DNA matches the DNA of someone
who currently lives there, that doesn’t necessarily mean your
ancestors came from that place. Likewise, your DNA might
match that of a modern-day African tribe, but your ancestors may
not have identified with that particular group.
Biogeographical tests such as DNA Testing Systems’ DNA Fingerprint
tests will estimate where in the world your ancestors originated. Yet scientists haven’t agreed upon definitions for even
broad genetic ethnicities, so if you test with more than one company, you may get different results.
By combining genetic genealogy and traditional genealogical
research methods, however, you can make headway in pinpointing
your family’s origins. As more people get tested and contribute
both their DNA test results and their family trees to online
databases (see myth 5 for more on these), scientists will be able to
identify additional patterns and draw better conclusions.

Genetic Genealogy For Beginners – Discovery your Family History Through DNA 101

 

 

 

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.

Genetic Genealogy Standards Chapter 1

 

 

 

The Genetic Genealogy Standards Committee presented these standards at the Salt Lake Institute of Genealogy in Jan. 2015.

This document is intended to provide standards and best practices for the genealogical community to follow when purchasing, recommending, sharing, or writing about the results of DNA testing for ancestry.

These Standards are intentionally directed to genealogist, not to genetic genealogy testing companies. As used in the Standards the term “genealogist” includes anyone who takes a genetic genealogy test, as well as anyone who advises a client, family member, or other individual regarding genetic genealogy testing. However, it is ultimately the responsibility of those taking a genetic genealogy test (“tester”) to understand and consider these standards before ordering or agreeing to take any genetic genealogy test.

Standards for Obtaining, Using and Sharing Genetic Genealogy Test Results

  1. Company Offerings. Genealogists review and understanding the different DNA testing products and tools offered by available testing companies, and prior to testing determine which company or companies are capable of achieving the genealogist’s goal(s).
  2. Testing With Consent. Genealogists only obtain DNA for testing after receiving consent, written or oral, from the tester. In the case of a deceased individual, consent can be obtained from a legal representative. In the case of a minor, consent can be given by a parent or legal guardian of the minor. However, genealogists do not obtain DNA from someone who refuses to undergo testing.
  3. . Raw Data. Genealogists believe that testers have an inalienable right to their own DNA test results and raw data, even if someone other than the tester purchased the DNA test.
  4.  DNA Storage. Genealogists are aware of the DNA storage options offered by testing companies, and consider the implications of storing versus not storing DNA samples for future testing. Advantages of storing DNA samples include reducing costs associated with future testing and/or preserving DNA that can no longer be obtained from an individual. However, genealogists are aware that no company can guarantee that stored DNA will be of sufficient quantity or quality to perform additional testing. Genealogists also understand that a testing company may change its storage policy without notice to the tester.
  5. Terms of Service. Genealogists review and understand the terms and conditions to which the tester consents when purchasing a DNA test.
  6. Privacy. Genealogists only test with companies that respect and protect the privacy of testers. However, genealogists understand that complete anonymity of DNA tests results can never be guaranteed.
  7. Access by Third Parties. Genealogists understand that once DNA test results are made publicly available, they can be freely accessed, copied, and analyzed by a third party without permission. For example, DNA test results published on a DNA project website are publicly available. 1 Except in situations where DNA testing is specifically mandated by law or court order. This type of mandated DNA testing may affect other Standard including Standards #3 (Raw Data), #6 (Privacy),
  8.  Sharing Results. Genealogists respect all limitations on reviewing and sharing DNA test results imposed at the request of the tester. For example, genealogists do not share or otherwise reveal DNA test results (beyond the tools offered by the testing company) or other personal information (name, address, or email) without the written or oral consent of the tester.
  9.  Scholarship. When lecturing or writing about genetic genealogy, genealogists respect the privacy of others. Genealogists privatize or redact the names of living genetic matches from presentations unless the genetic matches have given prior permission or made their results publicly available. Genealogists share DNA test results of living individuals in a work of scholarship only if the tester has given permission or has previously made those results publicly available. Genealogists may confidentially share an individual’s DNA test results with an editor and/or peer-reviewer of a work of scholarship. Genealogists also disclose any professional relationship they have with a for-profit DNA testing company or service when lecturing or writing about genetic genealogy.
  10. Health Information. Genealogists understand that DNA tests may have medical implications.
  11.  Designating a Beneficiary. Genealogists designate a beneficiary to manage test results and/or stored DNA in the event of their death or incapacitation. Standards for the Interpretation of Genetic Genealogy Test Results
  12.  Unexpected Results. Genealogists understand that DNA test results, like traditional genealogical records, can reveal unexpected information about the tester and his or her immediate family, ancestors, and/or descendants. For example, both DNA test results and traditional genealogical records can reveal misattributed parentage, adoption, health information, previously unknown family members and erros in well-researched family trees, among other unexpected outcomes.
  13. Different Types of Tests. Genealogists understand that there are different types of DNA tests, including Y-chromosome DNA (“Y-DNA”), mitochondrial DNA (“mtDNA”), Xchromosome (“X-DNA”), and autosomal DNA (“atDNA”) testing. Each test has advantages and limitations, and can be used in different ways for genealogical research. Often, multiple types of testing can be or must be used to test a hypothesis. Prior to testing, genealogists determine which type(s) of DNA testing is capable of achieving the genealogist’s goal(s).
  14.  Y-DNA and mtDNA Tests. Genealogists understand the current recommended minimum YDNA and mtDNA testing standards, guidelines for which are currently being drafted and will be found at http://www.GeneticGenealogyStandards.com when completed. Genealogists are aware that even after an initial mtDNA or Y-DNA test, additional testing (e.g., additional markers and/or sequencing) might be necessary in order to achieve the genealogist’s goal(s).
  15.  Limitations of Y-DNA Testing. Genealogists understand that Y-DNA test results reveal relationships among testers through their direct paternal lines. However, identification of the exact relationship or most recent common ancestor (“MRCA”) cannot be determined by Y-DNA test results alone.
  16. Limitations of mtDNA Testing. Genealogists understand that mtDNA test results reveal relationships among testers through their direct maternal lines. However, identification of the exact relationship or MRCA cannot be determined by mtDNA test results alone.
  17. Limitations of Autosomal DNA Testing. Genealogists understand that autosomal DNA test results, alone, can be used to confirm or deny first degree relationships with certainty (parent/child or full siblings). Genealogists understand that analysis of genealogical relationships beyond the first degree requires the combination of DNA test results and traditional genealogical records.
  18. Limitations of Ethnicity Analysis. Genealogists understand that ethnicity analysis is limited by the proprietary reference population database and algorithm utilized by the testing company, and thus understand that estimates can vary. Genealogists further understand that because individuals do not possess DNA from all ancestors, an ethnicity estimate can neither be predicted nor evaluated based solely on a genealogical family tree.
  19. Interpretation of DNA Test Results. Genealogists understand that there is frequently more than one possible interpretation of DNA test results. Sometimes, but not always, these possible explanations can be narrowed by additional testing and/or documentary genealogical research. Genealogists further understand that any analysis of DNA test results is necessarily dependent upon other information, including information from the tester, and that the analysis is only as reliable as the information upon which it is based.
  20.  DNA as Part of Genealogical Proof. Genealogists understand that no single piece of evidence, including evidence gathered from DNA testing, alone constitutes genealogical proof. Establishing genealogical proof requires thorough research in reliable relevant records, complete and accurate documentation and source citation, analysis and correlation of all evidence, resolution of conflicts caused by contradictory information, and a soundly reasoned written conclusion. For more information, see the Genealogical Proof Standard (www.bcgcertification.org).
  21. Citing DNA Test Results. Genealogists understand and use the current recommended minimum standards for citing DNA test results in reports to clients or in works of scholarship. Guidelines are currently being drafted and will be found at www.GeneticGenealogyStandards.com when completed.

Genetic Genealogy For Beginners – Chapter 2

 

 Basic Concepts

There are two basic concepts that form the foundation of Genetic Genealogy. (http://www.dnaftb.org

We humans inherit several “forms” of DNA, each of which can help genealogists research and confirm or reject different portions of a family tree. The DNA types are:

  • Mitochondrial DNA (mtDNA) found outside of the cell nucleus in tiny organelles called mitochondrial: (mitochondrion being the singular form);
  • Autosomal DNA (atDNA), which is composed of chromosomes 1-22 found in the cell nucleus, and

The sex-determining chromosomes, Y-DNA and X-DNA, also found in the cell nucleus.

The twenty-two autosomes and the X and Y chromsomes collectively are called nuclear DNA, as they are contained within the nucleus. 

Diagram of a human cell

The cell, the basic unit of life, uses genetic material called DNA to control the vast majority of its functions. DNA (short for Deoxyribonucleic-acid) is a component of the cell that carries a set of instructions development and operation of all living things. When two or more humans share segments of DNA, there is or was a shared common ancestor that lived in the past that connect those humans. Note: For African-American’s, DNA matches may not be readily identifiable, showing the real ancestor by surname; as migration occurred; name’ changes after the Civil War, forced name changes by slave owners, post traumatic stress disorder from slavery, adoptions by families of  children, lost of parents by hanging, jail and diseases from working in the fields and many other health related illnesses such as high blood pressure and cholesterol.

A very small percentage of DNA comprises genes, short segments of DNA that are used as the blueprint (map) to create a protein or an RNA (ribonucleic acid) molecule. A molecule of DNA is composed of a string of millions of smaller units called nucleotide. Together, two intertwined DNA molecules interact to form a single double-helix structure called a chromosome in the nucleus, or control center of the cell. A normal human cell has ninety-two long molecules of DNA that pair up to form forty-six double-stranded chromosomes. Each of these, in turn, forms a chromosome pair with another similar but not identical chromosome, to create twenty-three different chromosome pairs.

  • Nucleotide – The building block of DNA, it comes in four types that pair up in specific ways: Adenine (A), Cytosine (C), Guanine (G) and Thymine (T)
  • DNA (Deoxyribonnucleic acid) – A double-stranded molecule comprising two entwained strings of millions of different nucleotides
  • Gene – A region of DNA along a chromosome that encodes for a functional product such as a protein
  • Chromosome – A highly organized double helix of two DNA molecules
  • Chromosome Pair – Two complimentary chromosomes, one inherited from each parent

Double Helix courtesy of Danny Lela of the National Human Genome Research Institute access Dec. 2016

Chromosome chart courtesy of Darryl Lela of the National Human Genome Research Institute access Nov. 2016. This is called a Karyogram, which is all of the chromosomes of the human cell arranged in pairs in a numbered sequence from longer to shortest.

Note: Remember that the Mitochondria is outside of the nucleus. mtDNA and is not shown in this graphic.

The more DNA you share with someone, the more closer you are to that person. 

More on this and other topics in Chapter 3

Haplogroup

 

The Legal Genealogist: Term of the day: haplogroup

 

Source: http://thelegalgenealogist.com dated 22 Feb. 2017

This article was written from a Eurasian perspective. The definitions are correct.
The genetic genealogy glossary defiunition of haplogroup is “a genetic population group of people who share a common ancestor on the patrilineal or matrilineal line. Haplogroups are assigned letters of the alphabet, and refinements consist of additional number and letter combinations.”1

Okay. Great. What’s that mean?

Basically, if you think of all humans who’ve ever lived as part of the human race as a family tree, our haplogroup is what branch of the tree we can park ourselves on.

Everybody — male and female — has at least one haplogroup: our maternal haplogroup, as defined by our mitochondrial DNA (mtDNA). That’s the kind of DNA we all inherit from our mothers and that only females pass on to their children.2Our mtDNA haplogroup, then, is the branch of the tree we’re sitting on when the roots go back to the first woman from whom we descend: our mother’s mother’s mother’s mother.3

By itself, the mtDNA haplogroup tells us a great deal about our very deep ancestry many generations, even thousands of years in the past. But it also has some information we can use right now. It can tell us, for example, if our direct maternal line is of recent African or Native American origin. Or whether you, like me, have a maternal line that’s plain vanilla European.

Note that the fact that my maternal line is plain vanilla European doesn’t rule out having some more interesting ancestor from Africa or with Native American origin — it just means it isn’t my direct maternal line. It’s not in the direct line from my mother’s mother’s mother’s mother.

Only one of the major genetic genealogy companies offers mtDNA testing: Family Tree DNA. When you test at the HVR1 or HVR1+2 levels, the test looks at enough of the genetic markers to tell you what broad branch you belong to, represented by a letter like K or H. To get the specific branch — or twig! — the full mitochondrial sequence test (FMS) tests the entire mitochondria.4

Men also have another haplogroup, carried in their YDNA. That’s the kind of DNA that only males have and that’s passed from father to son largely unchanged through the generations.5 The YDNA haplogroup, then, is the branch of the tree a male is sitting on when the roots go back to the first man from whom he descends: his father’s father’s father’s father.6

By itself, the YDNA haplogroup tells the tale of deep ancestry just as the mtDNA haplogroup does, can indicate specific types of recent ethnicity — and is particularly useful genealogically to help distinguish between groups of men of the same surname: in my own research, for example, we thought our Shew line might be related to a specific Pennsylvania Shew line until we found that our line was haplogroup I and the Pennsylvania line was haplogroup R. Different branches of the human family tree entirely.

You will get a prediction of your YDNA haplogroup when you test with 23andMe and can get very specific YDNA haplogroup data from YDNA testing with Family Tree DNA, the only major genetic genealogy company that offers YDNA tests.


SOURCES

  1. ISOGG Wiki (http://www.isogg.org/wiki), “Haplogroup,” rev. 27 Dec 2016.
  2. Ibid., “Mitochondrial DNA tests,” rev. 15 Jan 2017.
  3. And so on back into time, often well before genealogical time. And see ibid., “Mitochondrial DNA haplogroup,” rev. 24 Sep 2017.
  4. Ibid., “Haplogroup,” rev. 27 Dec 2016.
  5. Ibid., “Y chromosome DNA tests,” rev. 4 Dec 2016.
  6. And so on back into time, often well before genealogical time. See also ibid., “Y-DNA Haplogroup ages”, rev. 19 Oct 2013.
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