Razib Khan One-stop-shopping for all of my content

February 1, 2011

My family’s Neandertal genes, ii

Last week I reported that it turns out that one of my siblings carry a possible Neandertal haplotype on the dystrophin gene. To review, it seems likely that ~3% of the average non-African’s genome is derived from Neandertal populations. But by and large this ancestral quantum seems broadly dispersed through the genome of individuals, so that there isn’t a particular set of loci which are Neandertal, as such. As an analogy, about ~20-25% of the genome of an average black American is derived from Europe because of white American ancestry. But you can’t usually predict from that on which locus the “white” alleles will be found. The main exception to this will be loci where you might suspect selection will be operative, such as those implicated in malaria defense (some of them have negative consequences).

The dystrophin haplotype though has higher frequencies in some populations than expectation. ~9% in non-Africans as a whole, and higher in some groups. So there was a reasonable expectation that people might find that they carried it snooping through their genomes. Now that my parents (RF and RM) have come through, as well as sibling #2 (RS2), I can show you this:

SNPs rs1456740 rs6628685 rs331370 rs2854965 rs6653863 rs331369 rs331368 rs331367 rs331366 RF A A T G A A T T T RS1 A/G A/A C/T G/G A/G A/C T/T T/T G/T Razib G A C G (not typed) C T T G RM A/G A/A C/T G/G A/G A/C T/T T/T G/T RS2 A A (no ...

January 27, 2011

Neandertal (haplotype) in the family!

There is pretty much a 100% probability that I carry Neandertal origin genes, since I’m Eurasian. That being said, I hadn’t looked too closely into the matter in regards to my own genome, because the whole “which SNPs are Neandertal” issue has been pretty dicey. But after the “Neandertal dystrophin” paper sniffing for whether you carry a specific Neandertal haplotype got a whole lot easier. The authors provided the markers and their associated haplotypes within the paper. So if the B006 haplotye is Neandertal, by looking at your markers in 23andMe through the browse raw data feature you can figure out what your lineage is, and see if you are indeed “Neandertal” on that locus. Since it’s on the X chromosome, males will carry only one copy of the gene. On the other hand, if you’re a woman you’ll have two copies, so ascertaining what specific combination of markers you have spanning a particular genomic segment can be more difficult (the results are not “phased,” so you don’t know if the allele is from the mother or father on any given genotype). But inferring the sequence of markers on a strand of DNA is much easier if ...

Powered by WordPress