Premium
The evolution of unusual chromosomal systems in sciarid flies: intragenomic conflict and the sex ratio
Author(s) -
Haig David
Publication year - 1993
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.1993.6020249.x
Subject(s) - biology , sex ratio , autosome , heterogametic sex , x chromosome , genetics , y chromosome , chromosome , sex linkage , meiotic drive , evolutionary biology , gene , population , demography , sociology
A model is presented for the evolution of the sciarid chromosomal system. In this model, a driving X chromosome caused female‐biased sex ratios. The drive was exploited by maternal autosomes that segregated with the X at spermatogenesis. Genes in mothers converted some of their XX daughters into sons by eliminating a paternal X from the embryonic soma. L chromosomes were derived from X chromosomes and favored male‐biased sex ratios. An X' chromosome arose that suppressed the effects of L chromosomes. The 1:1 sex ratio is a stalemate between the X' and X'X mothers causing all‐female broods and the L chromosomes in XX mothers causing all‐male broods. Any element (such as an L chromosome) that is preferentially transmitted through one sex will be selected to bias the sex ratio towards this sex.