title: Chromosomal location and gene paucity of the male specific region on papaya Y chromosome.
abstract: Sex chromosomes in flowering plants evolved recently and many of them remain homomorphic, including those in papaya. We investigated the chromosomal location of papaya's small male specific region of the hermaphrodite Y (Yh) chromosome (MSY) and its genomic features. We conducted chromosome fluorescence in situ hybridization mapping of Yh-specific bacterial artificial chromosomes (BACs) and placed the MSY near the centromere of the papaya Y chromosome. Then we sequenced five MSY BACs to examine the genomic features of this specialized region, which resulted in the largest collection of contiguous genomic DNA sequences of a Y chromosome in flowering plants. Extreme gene paucity was observed in the papaya MSY with no functional gene identified in 715 kb MSY sequences. A high density of retroelements and local sequence duplications were detected in the MSY that is suppressed for recombination. Location of the papaya MSY near the centromere might have provided recombination suppression and fostered paucity of genes in the male specific region of the Y chromosome. Our findings provide critical information for deciphering the sex chromosomes in papaya and reference information for comparative studies of other sex chromosomes in animals and plants.
authors.affiliation: Hawaii Agriculture Research Center, Aiea, HI 96701, USA.
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Yu
authors.forename: Shaobin
authors.initials: S
authors.lastname: Hou
authors.forename: Roman
authors.initials: R
authors.lastname: Hobza
authors.forename: F Alex
authors.initials: FA
authors.lastname: Feltus
authors.forename: Xiue
authors.initials: X
authors.lastname: Wang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Jin
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Skelton
authors.forename: Andrea
authors.initials: A
authors.lastname: Blas
authors.forename: Cornelia
authors.initials: C
authors.lastname: Lemke
authors.forename: Jimmy H
authors.initials: JH
authors.lastname: Saw
authors.forename: Paul H
authors.initials: PH
authors.lastname: Moore
authors.forename: Maqsudul
authors.initials: M
authors.lastname: Alam
authors.forename: Jiming
authors.initials: J
authors.lastname: Jiang
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Paterson
authors.forename: Boris
authors.initials: B
authors.lastname: Vyskot
authors.forename: Ray
authors.initials: R
authors.lastname: Ming
mesh_terms: D029441:Carica / Q000235:genetics*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D032461:Chromosomes, Plant / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D012091:Repetitive Sequences, Nucleic Acid; D019849:Sex Determination Processes