Posted by n/a at 5/11/2009 05:57:00 AM
The following entry from Polak showed up in my feed reader, though Polak seems to have removed it from his site.
Recent positive selection and male pattern baldnessI'm not terribly interested in quantitative differences here, but some qualitative ethnic differences in hairlines jump out at the observant. The straight-across hairline can add a vaguely disturbing note to already less-than-aesthetic Jewish physiognomies.
[This study] shows that recent selection has apparently pushed up the risk of baldness in Europeans, although obviously it's a lot more complex than that. The authors focus on the HapMap cohorts (Chinese, Japanese, Yoruba from Nigeria and Utah European Americans), which is a bit of a shame, because it would've been great to see the results for a variety of European groups. By the way, no subscription or payment is required for this one...
Axel M. Hillmer et al, Recent positive selection of a human androgen receptor/ectodysplasin A2 receptor haplotype and its relationship to male pattern baldness, Human Genetics, Published online: 17 April 2009, doi: 10.1007/s00439-009-0668-z
The Mediterranean or Latin development of pattern baldness involves recession of the frontal hairline and the development of vertex baldness. These two regions of hair loss expand and coalesce into the extensive type V pattern.this book chapter:
The Semitic (Jewish, Arabian) presentation of pattern alopecia involves progressive recession of the frontal hairline but there is no associated thinning on the vertex according to Ebling.
The Nordic presentation with a central lock of surviving hair was noted by Norwood in the development of his classification system. Ebling suggested the five stage system for Nordic races as shown below.
Human balding occurs in several patterns. These sometimes occur together or separately and occur at different frequencies. Some noteworthy patterns are: (A) Double point, forehead recession, widow’s peak; (B) Monk’s spot (usually A and B occur together; they are common in many European countries); (C) Line-of-march, common in the Mediterranean countries (e.g., Albert Einstein); (D) Single point forehead recession, common among Orientals (e.g., Mao Tse-tung).References (from the first site linked above):
* Norwood OT. Male pattern baldness: classification and incidence. South Med J. 1975 Nov;68(11):1359-65.
* Hamilton JB. Patterned loss of hair in man: types and incidence. Ana N Y Acad Dermatol 1951:53;708-28
* Camacho F, Montagna W. Trichology. Diseases of the pilosebaceous follicle. S. Karger Publishers Inc. Farmington, USA. 1998. ISBN: 3-8055-6672-7
* Norwood OT. Hair Transplant Surgery. Charles C Thomas Publishers, Springfield IL, USA, 1973. ISBN 0-398-02892-3