The hypothesis that ornaments can honestly signal quality only if their expression is
condition-dependent has dominated the study of the evolution and function of colour traits …

In many species, sex is determined by a system based on X and Y chromosomes, the latter
having lost much of their genetic activity. Y chromosomes have evolved independently many …

We develop models of the rates of evolution at sex-linked and autosomal loci and of the
rates of fixation of chromosomal rearrangements involving sex chromosomes and …

Differentiated sex chromosomes in mammals and other vertebrates evolved independently
but in strikingly similar ways. Vertebrates with differentiated sex chromosomes share the …

In theory, birds should control the sex ratio of the offspring they produce. In practice, we have
very limited evidence to support this idea because of our difficulty in sexing nestling birds. In …

Inherited enzyme variations, studied using electrophoresis, can be used as markers for the
identification of individuals, population structure analysis, the delineation of species …

Sex-determining mechanisms are highly variable between phyla. Only one example has
been found in which structurally and functionally related genes control sex determination in …

The presence or absence of the Y chromosome determines whether a mammalian embryo
develops as a male or female. In humans, genetic deletion analysis of" sex-reversed" …

Background In animals with heteromorphic sex chromosomes, dosage compensation of sex-
chromosome genes is thought to be critical for species survival. Diverse molecular …

ABSTRACT A new model for the evolution of reduced genetic activity of the Y sex
chromosome is described. The model is based on the process of genetic hitchhiking. It is …