Sex chromosomes are ubiquitous in birds but our understanding of how they originated and
evolved has remained incomplete. Recent work by Tsuda et al. on tinamou and ratite birds …

Theoretical work predicts natural selection to be more efficient in the fixation of beneficial
mutations in X-linked genes than in autosomal genes. This “fast-X effect” should be evident …

The cytological analysis of meiotic chromosomes is an exceptional tool to approach complex
processes such as synapsis and recombination during the division. Chromosome studies of …

The W chromosome is predicted to be subject to strong female-specific selection stemming
from its female-limited inheritance and therefore should play an important role in female …

Abstract Palaeognathous birds (Struthioniformes and Tinamiformes) have morphologically
conserved karyotypes and less differentiated ZW sex chromosomes. To delineate …

Reptiles display a wide diversity of sex-determining mechanisms ranging from temperature-
dependent sex determination (TSD) to genotypic sex determination (GSD) with either male …

Male secondary sexual characters (conspicuous ornaments, signals, colors) are among
nature's most striking features. Yet, it is unclear why certain groups of organisms are more …

A 0.6 kb Eco RI fragment (EE0. 6), cloned from the W chromosome of chickens, is a
nonrepetitive sequence and contains an exonlike sequence, ET15, which is likely a part of a …

Standard models of sex chromosome evolution propose that recombination suppression
leads to the degeneration of the heterogametic chromosome, as is seen for the Y …

Why are there two sexes in certain species, instead of one hermaphroditic sex? Why are Y
chromosomes shorter than X chromosomes, but only in certain lineages? I propose that …