Tuesday, November 06, 2007

Hair thickness, update   posted by Razib @ 11/06/2007 10:12:00 PM

This is an update on my previous post about hair thickness. In this post-genomic era the precision and data density we gain from more powerful techniques and sharper analytical techniques when it comes to genetic variation is not always supplemented by a concomitant increase in characterization of phenotypic variation. Sometimes it is best to look to older works from the lost age of physical anthropology; from page 63 of Racial Adaptations, the following data:

Area of the cross-section of hair in square millimeters
0.126 African
0.135 Blond European
0.193 Solomon Islander
0.204 Chinese

Weight in milligrams of a five-centimeter segment of an average hair
2.10 Brown haired European
2.15 Blond haired European
2.71 African
3.85 Black haired european
4.95 East Asian

Volume of five-centimeter segments of three kinds of hair two previous studies had in common
6.30 African
6.70 Blond haired European
10.2 East Asian

Weight-to-volume ratio
1:2.3 African
1:2.4 Blond haired European
1:1.2 East Asian