Submitted to: Plant Animal and Microbe Genomes Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2004
Publication Date: 1/14/2005
Citation: Yu, Q., Moore, P.H., Liu, Z., Uhm, T., Jones, M.R., Ackerrman, C.M., Paterson, A.H., Ming, R. 2005. Genomic analyses of the male specific region on the primitive Y chromosome in papaya. Plant Animal and Microbe Genomes Conference XIII. Abstract P506, p197. Interpretive Summary: Abstract only
Technical Abstract: The papaya male and hermaphrodite sexes have a primitive Y chromosome that provides a unique opportunity to study sex chromosome evolution. This primitive Y chromosome has a small male specific region (MSY) comprising only about 10% of the chromosome. This MSY shows severe suppression of recombination but only moderate sequence degeneration. The papaya system appears to be the most recently evolved XY system known to date and has the potential of providing insights into the question of how evolution of the sex chromosome began. We sequenced from 10 to 25 random sub-clones from 25 non-redundant bacterial artificial chromosomes (BACs) on the contig maps of the MSY. One hundred pairs of sequence specific primers were designed from random sequences of 17 of these BACs on the MSY to test the three sex forms of three papaya varieties and two related species. Only six out of the 100 pairs of primers amplified the correct sequence on at least one of the two wild species tested. This result demonstrates the divergence of the MSY within the family Caricaceae. Four BACs, appearing not to be male specific, were from two contigs constructed by hybridization of probes derived from male specific amplified fragment length polymorphism (AFLP) markers. Of the thirteen remaining BACs conformed to be male specific, all but one were from the three BAC contigs constructed by chromosome mapping. Ten putative functional genes were identified from sequence homology by sampling sequences on the MSY. Functional analysis of these putative genes is underway.