Thursday, May 23, 2013
Wednesday, May 08, 2013
Although confined to western European populations, this article seems to provide empirical evidence to validate several earlier papers on the theoretical relatedness of humans throughout the world.
Ralph P, Coop G (2013)
The Geography of Recent Genetic Ancestry across Europe.
PLoS Biol 11(5): e1001555. doi:10.1371/journal.pbio.1001555
The recent genealogical history of human populations is a complex mosaic
formed by individual migration, large-scale population movements, and other
demographic events. Population genomics datasets can provide a window into
this recent history, as rare traces of recent shared genetic ancestry are
detectable due to long segments of shared genomic material. We make use of
genomic data for 2,257 Europeans (in the Population Reference Sample
[POPRES] dataset) to conduct one of the first surveys of recent
genealogical ancestry over the past 3,000 years at a continental scale.
We detected 1.9 million shared long genomic segments, and used the lengths of
these to infer the distribution of shared ancestors across time and
geography. We find that a pair of modern Europeans living in neighboring
populations share around 2–12 genetic common ancestors from the last 1,500
years, and upwards of 100 genetic ancestors from the previous 1,000 years.
These numbers drop off exponentially with geographic distance, but since
these genetic ancestors are a tiny fraction of common genealogical
ancestors, individuals from opposite ends of Europe are still expected to
share millions of common genealogical ancestors over the last 1,000 years.
There is also substantial regional variation in the number of shared
genetic ancestors. For example, there are especially high numbers of common
ancestors shared between many eastern populations that date roughly to the
migration period (which includes the Slavic and Hunnic expansions into that
region). Some of the lowest levels of common ancestry are seen in the
Italian and Iberian peninsulas, which may indicate different effects of
historical population expansions in these areas and/or more stably
structured populations. Population genomic datasets have considerable power
to uncover recent demographic history, and will allow a much fuller picture
of the close genealogical kinship of individuals across the world.
Tuesday, April 30, 2013
The first ever public conference of its type, jointly sponsored by the Southern California Genealogical Society (SCGS) and ISOGG, is more than 75 % sold out. Attendance is limited to 350 people.
April 30 is the last day for reduced prices and the hotel is filling up.
Hotel reservations can be made at http://tinyurl.com/JamboreeHotel2013. Use code jamjama.
See Keynote speaker Spencer Wells of the National Geographic Project and Luncheon speaker Henry Louis Gates, Jr. plus many other well known names in the field. Program details are at
Registration is at http://www.scgsgenealogy.com/catalog/index.php?cPath=71 and the Early Bird Registration has been extended until May 7th.
The event is followed by the 3 day Genealogical Jamboree and many of the registrants plan to stay for both conferences.
Hope to see you there.
Alice Fairhurst, SCGS President and ISOGG Y-DNA Tree
Monday, April 22, 2013
*******DNA DAY SALE EXTENDED******
This year we began our commemoration of National DNA Day on April 19th. This coincides with the celebration by the National Human Genome Research Institute and the Smithsonian Institution's National Museum of Natural History's partnership to celebrate the 1953 discovery of the double helix and the 2003 completion of the Human Genome Project, which was April 19th.
However, DNA Day is celebrated worldwide on April 25th. Therefore, we've extended our sale! The usual conditions apply - orders must be made and paid for by 11:59 p.m. CDT on Thursday, April 25th.
Remember, we’ll offer a promotion on Y-DNA upgrades around Father’s Day, so be on the lookout for those details.
Click here to see and order all of our substantially discounted items!
Tuesday, April 09, 2013
Suppose that you’ve had your DNA genotyped by 23andMe or some other DTC genetic testing company. Then an article shows up in your morning newspaper or journal (like this one) and suddenly there’s an additional variant you want to know about. You check your raw genotypes file to see if the variant is present on the chip, but it isn’t! So what next? [Note: the most recent 23andMe chip does include this variant, although older versions of their chip do not.]
Genotype imputation is a process used for predicting, or “imputing”, genotypes that are not assayed by a genotyping chip. The process compares the genotyped data from a chip (e.g. your 23andMe results) with a reference panel of genomes (supplied by big genome projects like the 1000 Genomes or HapMap projects) in order to make predictions about variants that aren’t on the chip. If you want a technical review of imputation (and the program IMPUTE in particular), we recommend Marchini & Howie’s 2010 Nature Reviews Genetics article. However, the following figure provides an intuitive understanding of the process.
Continue reading ‘Learning more from your 23andMe results with Imputation’.
Friday, April 05, 2013
In Build 36 I had 483 matches in Family Finder;
After the first stage of the conversion I had 423 matches, then 438 and finally 443. This week I have 538 Family Finder matches.
I have identified the common ancestor/s with 14 matches.
At 23andme I have 1825 matches and have identified the common ancestor with 16.
At AncestryDNA I have 4100+ matches and have identified the common ancestor in the pedigrees with over 100 matches. I am looking forward to getting segment location and sizes from AncestryDNA so I can make a better comparison with FTDNA's Family Finder and 23andme's Relative Finder.
All three autosomal DNA raw results are now reported in Build 37.
Wednesday, April 03, 2013
FTDNA has announced they will have a lower priced mitochondrial, mtDNA, test later this year.
The cost of their autosomal DNA test, Family Finder, has not been reduced. The test can be taken by both males and females and can find genetic connections back around 6 generations. At the 6th cousin level you will share less than 1% of your DNA with a 6th cousin.
23andMe has reduced the cost of their autosomal DNA test, Relative Finder, to $99.00. People outside of the United States should look at the shipping cost before placing the order. The reduction from $299.00 has made this a more affordable test. The results of the Relative Finder test are similar to Family Finder.
AncestryDNA, a part of Ancestry.com, has reduced the cost of their autosomal DNA test to $99.00. It is not available to persons outside of the USA. Using the pedigrees uploaded to Ancestry.com and a phasing formula developed by them, they are able to match DNA segments to pedigrees in their database. However, unlike FTDNA and 23andme, they do not provide a chromosome browser so you can see where your matches are on each chromosome. This means you could find a pedigree match but that person may not be the one you share DNA with.
Sunday, March 10, 2013
Article Genetic Genealogy Comes of Age: Perspectives on the Use of Deep-Rooted Pedigrees in Human Population Genetics.
The full article is available:
Genetic Genealogy Comes of Age: Perspectives on the Use of Deep-Rooted Pedigrees in Human Population Genetics.
M H D Larmuseau, A Van Geystelen, M van Oven, R Decorte
UZ Leuven, Laboratory of Forensic Genetics and Molecular Archaeology, Leuven, Belgium; Department of Imaging and Pathology, KU Leuven, Forensic Medicine, Leuven, Belgium; KU Leuven, Department of Biology, Laboratory of Biodiversity and Evolutionary Genomics, Leuven, Belgium.
American Journal of Physical Anthropology (impact factor: 2.82). 02/2013; DOI:10.1002/ajpa.22233
In this article, we promote the implementation of extensive genealogical data in population genetic studies. Genealogical records can provide valuable information on the origin of DNA donors in a population genetic study, going beyond the commonly collected data such as residence, birthplace, language, and self-reported ethnicity. Recent studies demonstrated that extended genealogical data added to surname analysis can be crucial to detect signals of (past) population stratification and to interpret the population structure in a more objective manner. Moreover, when in-depth pedigree data are combined with haploid markers, it is even possible to disentangle signals of temporal differentiation within a population genetic structure during the last centuries. Obtaining genealogical data for all DNA donors in a population genetic study is a labor-intensive task but the vastly growing (genetic) genealogical databases, due to the broad interest of the public, are making this job more time-efficient if there is a guarantee for sufficient data quality. At the end, we discuss the advantages and pitfalls of using genealogy within sampling campaigns and we provide guidelines for future population genetic studies.
Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.
Tuesday, March 05, 2013
The sixth Future of Genomic Medicine Conference takes place this week in La Jolla, California. Details are here: http://www.scripps.org/events/the-future-of-genomic-medicine-vi-march-7-2013/.
George Church of the Personal Genome Project is one of the speakers.