â€œIâ€™m a complete neophyte about DNA for genealogy. Iâ€™m wondering if there is any reason to test myself, and my mother. Since the mtDNA seems to trace the maternal lineâ€¦ is it enough to test just one of us or is there something to be learned by testing both of us?â€
This is a great question, one that many people who are new to genetic genealogy ask.Understanding how mtDNA and Y-DNA are inherited is one of the most challenging aspects of genetic genealogy.I always think of them as mirror images; if you chart your family tree, the Y-DNA travels down the far left line (from your fatherâ€™s fatherâ€™s fathersâ€™ fatherâ€¦) while the mtDNA follows the far right line (from your motherâ€™s motherâ€™s motherâ€™s motherâ€¦).Here is my response to her comment:
Although the article in today’s New York Times – “DNA Tests Offer Immigrants Hope or Despair” by Rachel L. Swarns – uses traditional paternity or maternity tests and not genetic genealogy tests, the emotional results of the tested can often be the same. What if DNA proves that your father isn’t your biological father? What happens when there is uncontestable proof that there was an NPE (non-paternal event) in your great-grandfather’s ancestry?
According to the article, federal officials in the Immigration Department are using “genetic testing to verify the biological bonds between new citizens and the overseas relatives they hope to bring here, particularly those from war-torn or developing countries where identity documents can be scarce or doctored.”
I get visitors from search engines nearly everyday looking for information about the startup business 23andMe. Iâ€™ve briefly mentioned 23andMe before, but I thought Iâ€™d see how much information I could gather doing a brief online search.
The website describes the venture:
â€œ23andMe is an early stage startup developing tools and producing content to help people make sense of their genetic information. Our goal is to take advantage of new genotyping technologies and help consumers explore their genetics, informed by cutting edge science.
â€œCombining computer science, biology and informatics, we are at the cutting edge of a new era of genetics. Genome deciphering technologies have reached affordable levels, allowing consumer access. This information has the potential to empower both individuals and society in a way that will deliver tremendous value. For the individual, such information will provide personal insight into ancestry, genealogy and health. For society, the collection of genotypic and phenotypic information on a large scale will provide scientists with novel avenues for research.
Genes in fashion â€“ The anthropology department of the CaliforniaStateUniversity has tested the DNA of hundreds of students to create an exhibit called “Immigrants All! Our Migration Tales and Genetic Trails” in the departmentâ€™s museum.
To Whom Else Does Your DNA Belong? â€“ A response to reporter Amy Harmonâ€™s recent story in the New York Times.Although I donâ€™t agree with the strict opposition voiced in this student article, the title is very similar to the title I chose for my own response.
McCoy tempers in famed feud may have genetic cause â€“ Many of the McCoyâ€™s, one of Americaâ€™s most famous feuding families, have a genetically inherited disease caused Von Hippel-Landau which cause tumors of the adrenal gland.This can lead to high blood pressure and hot tempers.It turns out that geneticists have been studying and publishing about the family for over 30 years and have traced the disease through at least 4 generations.
Rogue-gene discovery could end family’s tragedy â€“ Another story about using genetics and genealogy to trace the distribution of a devastating mutant gene through a family.This gene, which triggers stomach cancer, has ravaged at least 5 generations of a family in New Zealand.
I recently profiled the website DnaTube which hosts videos and animations that explain various facets of genetics and DNA.Another source of valuable information is the Learn.Genetics website hosted by the Genetic Science Learning Center at the University of Utah.
According to the website:
“The Genetic Science Learning Center is an outreach education program located in the midst of bioscience research at the University of Utah. Our mission is to help people understand how genetics affects their lives and society.Our educational resources provide accurate and unbiased information about topics in genetics and bioscience. Designed for non-research audiences, our materials are interactive and jargon-free, target multiple learning styles, and often convey concepts through visual elements.“
An article in today’s New York Times, “Stalking Strangers’ DNA to Fill in the Family Tree” by Amy Harmon, looks at the extremes that some genetic genealogists have gone to to ‘obtain’ DNA from other people for analysis. The genetic genealogists in the article have stalked potential relatives and one keeps a DNA kit in his fridge awaiting his uncooperative father’s demise.
I recently asked my father’s first cousin to take a DNA test since he possessed the only surviving mtDNA from my great-grandmother, and orphan. The two lines had connected in 30 or 40 years, but once I made contact he was very interested in taking the test. The results provided the only clues I have regarding my great-grandmother’s ancestry. If that source had been unwilling to participate, I own some letters that my great-grandmother had written and I could have analyzed the DNA from the envelopes. I do understand the desire to analyze someone else’s DNA, but stalking people and waiting for them to die seems a bit extreme.
I just happened across a new site called DnaTube.com Scientific Video Site. According to the website:
“DnaTube is a scientific research site providing video based studies, lecturers and seminars. Our goal is to contribute science by generating self-growing community who shares their scientific experiences. Most of DnaTube members are graduate students from universities of all countries.”
There’s a very brief introduction to DNA, genes, and inheritence.Â Even better, I watched a FASCINATING video showing the 3D structure of a mitochondria.Â For anyone who’s purchased a mtDNA genealogy test, this is a great video to understand more about mitochondria. I also watched a very cool video about red blood cells.
It looks as thought DnaTube is just starting, so check back often to see what’s new and interesting.
The CCR5 gene encodes a chemokine receptor (a long name for a protein that sits in the walls of our cells).When the body has been invaded by a pathogen such as a cold virus, CCR5 plays an important role in fighting that virus.Smart viruses such as HIV-1, however, hijack the CCR5 protein and use it to sneak into CD4+ T cells & macrophages.
In some populations the CCR5 gene has experienced a mutation that deleted 32 basepairs in the gene sequence.The mutation prevents the expression of the protein on the cell surface.As a result, people with this mutation show some degree of protection from certain viruses.In fact, homozygosity of the CCR5-D32 allele (meaning BOTH copies of the gene are mutated) leads to “nearly complete resistance to HIV-1 infection.”People with only 1 copy are as much as 70% resistant! Surprisingly, homozygotes do not show any other problems as a result of the mutation.
My first foray into genetic genealogy took place in 2003 when I ordered the mtDNAPlus (which sequences both HVR1 and HVR2) from Family Tree DNA.
Like so many other genealogists, I had been unable to trace my maternal line as far as I would have hoped.My most distant ancestor, Sarah L. Bodden, was born in 1846 in the Cayman Islands and had died in 1914 in Honduras.No one knew anything about Sarahâ€™s parents or her life, and given the location and the difficulty of research I felt that this line had little prospect of development.It was a perfect opportunity to employ genetics.
Inside (almost) every one of my 50 trillion cells (thatâ€™s 50,000,000,000,000!!!) there is a tiny circle of DNA that has been given to me, most likely unchanged, in a direct line from Sarah through 125 years, 5 generations, and across 1750 miles.By sequencing a small part of the DNA I could identify from which branch of the â€œmaternal family treeâ€ Sarah descended.Based on the information I had managed to put together, I predicted that Sarah was a descendant of English immigrants who settled the Cayman Islands and would thus possess mtDNA belonging to a European lineage.
Senator Edward Kennedy (D-Massachusetts) proposed a piece of legislation before the United States Senate on 1 March 2007 called the â€œLaboratory Test Improvement Act.â€The Act is proposed as a series of amendments to the Federal Food, Drug, and Cosmetic Act (FFDCA).
Sen. Kennedyâ€™s statement(pdf) before the Senate, found in the Congressional Record from this month, defines his goal as â€œ[ensuring] the quality of clinical tests used every day in hospitals and doctorsâ€™ offices across the country.â€Additionally, he pointed out that the â€œtests are being used to diagnose illnesses, predict who is most susceptible to specific diseases, and identify persons who carry a genetic disease that they could pass on to their children.â€