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J Man
06-29-2014, 08:49 PM
I have a few questions about the origins of the main lactase persistence mutation T−13910 found among Europeans. I will start with this. Is it likely that the T−13910 mutation originated in just one person thousands of years ago?

lgmayka
06-29-2014, 10:50 PM
As far as I know, this paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950831/) is still the best work on the origin of T-13910. The abstract says:
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A single-nucleotide variant, C/T-13910, located 14 kb upstream of the lactase gene (LCT), has been shown to be completely correlated with lactase persistence (LP) in northern Europeans. Here, we analyzed the background of the alleles carrying the critical variant in 1,611 DNA samples from 37 populations. Our data show that the T-13910 variant is found on two different, highly divergent haplotype backgrounds in the global populations. The first is the most common LP haplotype (LP H98) present in all populations analyzed, whereas the others (LP H8H12), which originate from the same ancestral allelic haplotype, are found in geographically restricted populations living west of the Urals and north of the Caucasus. The global distribution pattern of LP T-13910 H98 supports the Caucasian origin of this allele. Age estimates based on different mathematical models show that the common LP T-13910 H98 allele (∼5,00012,000 years old) is relatively older than the other geographically restricted LP alleles (∼1,4003,000 years old).
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In other words, the 13910 C > T mutation has occurred more than once, but:

- The vastly distributed haplotype (H98) has a single origin less than 12,000 years ago

- Other haplotypes (H8-H12) originate from a similar background but are found only near the Pontic Steppe, and are younger.

J Man
06-29-2014, 11:51 PM
As far as I know, this paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950831/) is still the best work on the origin of T-13910. The abstract says:
---
A single-nucleotide variant, C/T-13910, located 14 kb upstream of the lactase gene (LCT), has been shown to be completely correlated with lactase persistence (LP) in northern Europeans. Here, we analyzed the background of the alleles carrying the critical variant in 1,611 DNA samples from 37 populations. Our data show that the T-13910 variant is found on two different, highly divergent haplotype backgrounds in the global populations. The first is the most common LP haplotype (LP H98) present in all populations analyzed, whereas the others (LP H8–H12), which originate from the same ancestral allelic haplotype, are found in geographically restricted populations living west of the Urals and north of the Caucasus. The global distribution pattern of LP T-13910 H98 supports the Caucasian origin of this allele. Age estimates based on different mathematical models show that the common LP T-13910 H98 allele (∼5,000–12,000 years old) is relatively older than the other geographically restricted LP alleles (∼1,400–3,000 years old).
---

In other words, the 13910 C > T mutation has occurred more than once, but:

- The vastly distributed haplotype (H98) has a single origin less than 12,000 years ago

- Other haplotypes (H8-H12) originate from a similar background but are found only near the Pontic Steppe, and are younger.

This is some excellent information thank you. Is there a way for us to check our haplotypes on 23andme I wonder?