Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Harkess, Alex [1], Leebens-Mack, Jim [2].

Identifying Sex Determination Genes on the Young Asparagus Y Chromosome.

Garden asparagus (Asparagus officinalis), a dioecious species with a recently evolved homomorphic sex chromosome pair, is ideal for studying the earliest events in sex chromosome evolution. A proposed evolutionary path from hermaphroditism to dioecy and a sex chromosome pair would involve the origin of a Y chromosome through cessation of recombination between a suppressor of female function and a promoter of male function. We have explored this hypothesis by genetically mapping sex determination to a 1.8 Mb non-recombining region on the asparagus Y chromosome. We have identified four independent male-to-hermaphrodite mutants that implicate a single gene in this non-recombining region as responsible for dominantly interrupting pistil development. Anther development is not affected in these mutants but male to female conversions are seen in two mutants with deletions spanning the 1.8 Mb non-recombining sex determination region. This region contains 14 annotated genes including defective in tapetal development and function 1 (TDF1). In support of a model proposed by Charlesworth & Charlesworth (The American Naturalist 1978), these finding imply that the origin of a non-recombining sex determining region on the Asparagus proto-Y chromosome involved the linkage of a male promoting gene with a dominant female suppressor.

1 - University of Georgia, Department of Plant Biology, Athens, GA, 30602, USA
2 - University Of Georgia, 4503 Miller Plant Sciences, Athens, GA, 30602, USA

Keywords:
dioecy
chromosome evolution
Gender determination
Sex chromosome.

Presentation Type: Oral Paper
Session: 2, Evolution and Development
Location: 200/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 10:30 AM
Number: 2010
Abstract ID:699
Candidate for Awards:None