ScienceDaily (Dec. 29, 2008) — Anyone who has watched crime dramas on TV knows that forensic scientists can use DNA “profiling” to identify people from evidence gathered at a crime scene, establish a paternity link or help free an innocent person who has been wrongly jailed. A lesser known but rapidly growing application of DNA profiling is tracing a person’s paternal ancestry—a process known as genetic genealogy.
The laboratories performing this testing often differ in their results, making data comparison between labs difficult and casting doubt on reported genetic matches. Researchers at the National Institute of Standards and Technology (NIST) recently published a paper with recommendations for genealogy testing that they hope will improve the accuracy and reliability of the product.
A man’s paternal lineage can be traced using the DNA on his Y chromosome (Y-DNA), which, like many European surnames, passes from father to son. DNA profiling provides a genetic path that follows the surname through the years. Women who wish to know their ancestry can ask their father, brother, paternal uncle or paternal grandfather to take the test for them.
Genetic genealogy works by studying the sequences of repeating nucleotide (the base components of DNA) patterns on the Y chromosome known as short tandem repeats (STRs). Each STR is considered a separate marker for potential genetic matching because the number of times it is repeated will be the same for related males. For example, a person may have one STR sequence that repeats 12 times, another 11 times, a third 17 times and so on. If another male has a Y chromosome with a high percentage of the same STRs, it is considered likely that they share a common ancestor. Accurately counting the number of repeats is a tricky task and the source of much of the error in genetic genealogy tests, causing genealogists to make incorrect matches or miss family connections altogether.
In their paper, the NIST researchers explain the basis for the differing interpretations and recommend a solution using the agency’s certified reference material for human Y-chromosome DNA profiling (Standard Reference Material 2395), a collection of Y-STR markers that can serve as a means for genetic labs to calibrate their testing equipment. The researchers “strongly encourage [SRM 2395’s] use to enable compatible and calibrated measurements to be made between different Y-STR testing laboratories.”
Their sentiment is echoed by an editorial in the Journal of Genetic Genealogy that says of the NIST paper, “The advantages of having industry-wide standards are compelling for both buyers and sellers of genetic genealogy services.”
Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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quote:Originally posted by MindoverMatter718: DNA Profiling For Tracing Parental Ancestry Becomes More Accurate And Reliable
So much for Erroneous-E, and his desperate pleas for Y chromosomes being a thing of the past..... Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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To think that they've only recently caught onto the idea that standardized Y-DNA profiling referential materials was needed for all existing discrete labs, is what I find particularly interesting. This has long been the case for mtDNA; can someone say for example, profiling with the aid of the Cambridge Reference Sequencing material?!
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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quote:Originally posted by The Explorer: To think that they've only recently caught onto to the idea that standardized Y-DNA profiling referential materials was needed for all existing discrete labs, is what I find particularly interesting.
Perhaps since Y-DNA is more discriminating when testing genealogy since it's passed trough the male. You know "they" don't want to admit to African men taking European wives/partners hundreds or even thousands of years ago. Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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^^^It was a joke you idiot. Did I uhh......hit a nerve?? Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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Well, successful mtDNA transmission is generally through the female, which makes it too discriminating in that sense, that is -- from the uniparental standpoint. In fact, the overall human mtDNA gene pool is more diverse than the Y DNA counterpart. This greater diversity plays a role in no small part, contributing to the relatively greater complexity in tracking complicated demographic events associated with mtDNA expansions than those of Y DNA. It could be said that the relatively lower diversity of the overall identified male DNA pool created a lax-culture with regards to a serious need for a standard Y DNA reference material system. I alluded to this issue of diversity before...
mtDNA may paint a somewhat more complex picture than their Y counterparts, in no small part due to the far much deeper root [taking us back to the earliest traceable MRCA] of the maternal line of contemporary human populations, and hence much greater time depths in which complex patterns of demic processes would have taken place than those of the Y chromosome counterpart, leaving room for relatively larger margins of error in dating earlier coalescent ages, and in which case, there is the real possibility that the evidence of earlier distribution pattern of mtDNA clusters under study could well have been erased by subsequent demographic processes [to put it in a language not too different from Salas et al. 2002].
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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quote:Originally posted by MindoverMatter718: Perhaps since Y-DNA is more discriminating when testing genealogy since it's passed trough the male. You know "they" don't want to admit to African men taking European wives/partners hundreds or even thousands of years ago.
What about in this day and age with folks like Marc Washington. I wonder what he feels like about his descendants having "albino" ancestry. LOLPosts: 26285 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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No nerves to hit at all. Don't be so hard on yourself; after all you said it... flim flam man. Posts: 2118 | From: midwest, USA | Registered: Aug 2007
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