Z and W Sex Chromosomes in the Cane Toad (Bufo Marinus)

Overview

Journal Chromosome Res

Date 2009 Nov 26

PMID 19936947

Citations 17

Authors

John Abramyan

Tariq Ezaz

Jennifer A Marshall Graves

Peter Koopman

Affiliations

Soon will be listed here.

Abstract

The cane toad (Bufo marinus) is one of the most notorious animal pests encountered in Australia. Members of the genus Bufo historically have been regarded as having genotypic sex determination with male homogamety/female heterogamety. Nevertheless, as with many toads, karyotypic analyses of the cane toad have so far failed to identify heteromorphics sex chromosomes. In this study, we used comparative genomic hybridization, reverse fluorescence staining, C-banding, and morphometric analyses of chromosomes to characterize sex chromosome dimorphism in B. marinus. We found that females consistently had a length dimorphism associated with a nucleolus organizer region (NOR) on one of the chromosome 7 pair. A strong signal over the longer NOR in females, and the absence of a signal in males indicated sex-specific DNA sequences. All females were heterozygous and all males homozygous, indicating a ZZ/ZW sex chromosomal system. Our study confirms the existence of sex chromosomes in this species. The ability to reliably identify genotypic sex of cane toads will be of value in monitoring and control efforts in Australia and abroad.

Citing Articles

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Evolution and dosage compensation of nucleolar organizing regions (NORs) mediated by mobile elements in turtles with female (ZZ/ZW) but not with male (XX/XY) heterogamety.

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Hybridization and introgression between toads with different sex chromosome systems.

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