title: Identification of Sex Chromosomes by Means of Comparative Genomic Hybridization in a Lizard, Eremias multiocellata.
abstract: Eremias multiocellata is a viviparous lizard that is known to exhibit temperature-dependent sex determination (TSD). Conventional Giemsa staining under light microscope examination has identified the karyotype of this species to be 2 n=36 I+2 m, with no detectable heteromorphic sex chromosomes. However, a highly differentiated female-specific chromosome, W, which is homomorphic with the Z chromosome, is found in the present study by the high-resolution cytogenetic method of comparative genomic hybridization (CGH). The results show that E. multiocellata is a viviparous lizard with both TSD and ZW heterogametic sex chromosomes. Despite the fact that a different sex ratio of male offspring was found in two populations (separated by an altitude of 1400 m) in previous incubation experiments, we demonstrate, using genomic in situ hybridization (GISH), that there is no significant chromosomal loss or acquisition between the two populations. This suggests that temperature may play a more important role in lowland populations. These results most likely indicate that E. multiocellata is transitioning between the evolutionary processes of TSD and genotypic sex determination (GSD) systems, and also give clues to the effect of TSD versus GSD in this process.
authors.affiliation: 1 School of Life Science, Lanzhou University, Lanzhou 730000, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Wang
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Tang
authors.forename: Ying
authors.initials: Y
authors.lastname: Xin
authors.forename: Feng
authors.initials: F
authors.lastname: Yue
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Yan
authors.forename: Bingbing
authors.initials: B
authors.lastname: Liu
authors.forename: Bei
authors.initials: B
authors.lastname: An
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
mesh_terms: D063147:Animal Distribution; D000818:Animals; D005260:Female; D007621:Karyotyping; D008116:Lizards / Q000235:genetics*; D008297:Male; D009693:Nucleic Acid Hybridization; D012730:Sex Chromosomes; D012732:Sex Determination Analysis / Q000662:veterinary; D012733:Sex Differentiation / Q000235:genetics
keywords: TSD; comparative genomic hybridization; reptile; sex chromosome; viviparity