Hypertrichosis, or "Hairy
Ears": a Y-linked trait ? [ Not ] []
Growth of thick hair on the
pinnae of the external ears of males has long been
presented in genetics textbooks as a Y-linked trait, common in some south Indian
populations. The illustration shows three brothers. Molecular
population studies () indicate that men with hairy ears do
not share any common Y-chromosome
DNA sequences. Also,
frequencies of Y-chromosome
haplotypes shared among men with hairy ears are no different than
those in non-hairy control groups from the same population. The data thus indicate that
hairy-eared men are unrelated and do not share a common Y-linked allele. The trait may
instead be a sex-limited trait
(like beard growth) influenced by one or more autosomal loci (Carr
& Kasbekar, 2022).