Human evolution and fur

[The Grand Nudger]

Your leg hair is handled by the gene that codes for keratin, as I mentioned in my post. It's spindly and sparse because this gene does not code thick strong fur like the corresponding gene in a chimp would. It doesn't have to, your skin is much better weatherproofing than a chimps skin (which is better weatherproofing than most itself). However, this little bit of genetic magic is a "gift" from a common ancestor, so we both have hair, ours is simply different than theirs.

Let wonder lead you to knowledge....

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Human genomic DNA containing two type II keratin genes, one coding for keratin 1 (K1, a 68-kD basic protein) and another closely linked type II gene 10–15 kb upstream (K?, gene product unknown), was isolated on a single cosmid clone. EcoRI restriction fragments of the cosmid were subcloned into pGEM-3Z, and specific probes comprising the C-terminal coding and 3 noncoding regions of the two genes were constructed. The type II keratin genes were localized by in situ hybridization of the subcloned probes to normal human lymphocyte chromosomes. In a total of 70 chromosome spreads hybridized with the K? probe (gHK?-3, PstI, 800 bp), 36 of the 105 grains observed were on chromosome 12, and 32 of these were clustered on the long arm near the centromere (12q11–13). In 100 labeled metaphases hybridized with the K1 probe (gHK1–3, BamHI-PstI, 2100 bp), 53 grains localized to chromosome 12 and 46 of these were found in the same region (q11–13). Therefore, both the gene for human keratin 1, a specific marker for terminal differentiation in mammalian epidermis, and another closely linked unknown type II keratin gene (K?, 10–15 kb upstream of K1) are on the long arm (q11–13) of human chromosome 12.

http://www.springerlink.com/content/pv63787x2647780p/

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That the sort of explanation you're after?