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Title: AUTOSOMAL DEGENERATION AS THE PROCESS FOR THE EVOLUTION OF A PRIMITIVE Y CHROMOSOME IN PAPAYA

Author
item QUINGYI, YU - HARC
item Moore, Paul
item HOU, SHAOBIN - UNIV HAWAII
item JIANG, JIMING - UNIV WISCONSIN
item PATERSON, ANDREW - UNIV GEORGIA
item VYSKOT, BORIS - CZECH ACADEMY OF SCIENCES
item MING, RAY - UNIV ILLINOIS

Submitted to: International Congress of Plant Molecular Biology
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2006
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Plant sex chromosomes, in contrast to those in animals, evolved recently and only a few are heteromorphic. Genomic analyses of the homomorphic sex chromosomes of papaya show features of the early stages of sex chromosome evolution. Sequence analysis of 20% of the male specific region (MSY) shows that in spite of its relatively recent origin from an autosome, the divergence of MSY sequences from its X chromosome counterparts is extensive. This sequence divergence involves multiple DNA alterations including duplications and insertions of organelle DNA and retroelements that have led to extreme gene paucity; only two functional genes have been identified in 1 Mbp of MSY sequences. Chromosome fluorescent in situ hybridization mapping of Y specific BACs showed that the MSY is located near the centromere. The MSY centromeric location and divergence of sequence suggests that evolution of the sex chromosome may have utilized the centromere mechanisms for suppression of recombination. Such an origin for Y chromosomes could be advantageous for preserving sex without destruction of other gene functions as would have been the case with chromosomal rearrangements. Our finding demonstrates a novel mechanism in sex chromosome evolution.