Low mitochondrial variability in birds may indicate Hill-Robertson effects on the W chromosome

• Interference among loci subject to selection ( the Hill Robertson effect) may considerably reduce levels of adaptation and variability in genomic regions that lack recombination. Y- or W chromosomes are particularly vulnerable to such effects, since they represent large, non-recombining blocks of genetic material. In birds, the W chromosome and mitochondrial genomes are both maternally transmitted, and hence fail to recombine with each other, whereas in mammals the Y chromosome is paternally transmitted. We show here that mitochondrial DNA sequence diversity is reduced in non-ratite birds compared with mammals. After considering possible confounding factors, such as differences in generation times, mutation rates and demography, we conclude that Hill-Robertson effects associated with the W chromosome provide the most likely explanation for this difference.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

W chromosomes

mitochondria

Hill-Robertson effects

birds

mammals

Biology

Biologi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)