▪ Abstract Meiotic chromosomes have been studied for many years, in part because of the
fundamental life processes they represent, but also because meiosis involves the formation …

We have used immunofluorescent localization to examine the distribution of MLH1 (MutL
homolog) foci on synaptonemal complexes (SCs) from juvenile male mice. MLH1 is a …

Chickens and the great flightless emu belong to two distantly related orders of birds in the
carinate and ratite subclasses that diverged at least 80 million years ago. In the first ZOO …

The duck-billed platypus is an extraordinary mammal. Its chromosome complement is no
less extraordinary, for it includes a system in which ten sex chromosomes form an extensive …

Recent progress of chicken genome projects has revealed that bird ZW and mammalian XY
sex chromosomes were derived from different autosomal pairs of the common ancestor; …

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

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 …

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 …

Unlike mammals, birds have a ZZ male/ZW female sex-determining system. In most birds,
the Z is large and gene rich, whereas the W is small and heterochromatic, but the ancient …

Here, for the first time, we describe the karyotype of Myiopsitta monachus (Psittacidae, Arini).
We found 2n= 48, corresponding to the lowest diploid number observed in Neotropical …