phylogeny and sex chromosomes

[Jim Garey]

Can somebody please direct me to references on the occurence of 
different chromosomal sex determination systems among different 
metazoan phyla?  For example, XX, XY in many vertebrates, X/A ratio 
in some insects.  I am interested in papers in which people have 
surveyed these systems across many phyla.

Thanks,  Jim Garey

_____________________________________
Dr. James R. Garey
Department of Biological Sciences
Duquesne University
Pittsburgh, PA 15282

412-396-6322 (voice)
412-396-5907 (fax)
garey at next.duq.edu