| Title |
The Staurotypus Turtles and Aves Share the Same Origin of Sex Chromosomes but Evolved Different Types of Heterogametic Sex Determination
|
|---|---|
| Published in |
PLOS ONE, August 2014
|
| DOI | 10.1371/journal.pone.0105315 |
| Pubmed ID | |
| Authors |
Taiki Kawagoshi, Yoshinobu Uno, Chizuko Nishida, Yoichi Matsuda |
| Abstract |
Reptiles have a wide diversity of sex-determining mechanisms and types of sex chromosomes. Turtles exhibit temperature-dependent sex determination and genotypic sex determination, with male heterogametic (XX/XY) and female heterogametic (ZZ/ZW) sex chromosomes. Identification of sex chromosomes in many turtle species and their comparative genomic analysis are of great significance to understand the evolutionary processes of sex determination and sex chromosome differentiation in Testudines. The Mexican giant musk turtle (Staurotypus triporcatus, Kinosternidae, Testudines) and the giant musk turtle (Staurotypus salvinii) have heteromorphic XY sex chromosomes with a low degree of morphological differentiation; however, their origin and linkage group are still unknown. Cross-species chromosome painting with chromosome-specific DNA from Chinese soft-shelled turtle (Pelodiscus sinensis) revealed that the X and Y chromosomes of S. triporcatus have homology with P. sinensis chromosome 6, which corresponds to the chicken Z chromosome. We cloned cDNA fragments of S. triporcatus homologs of 16 chicken Z-linked genes and mapped them to S. triporcatus and S. salvinii chromosomes using fluorescence in situ hybridization. Sixteen genes were localized to the X and Y long arms in the same order in both species. The orders were also almost the same as those of the ostrich (Struthio camelus) Z chromosome, which retains the primitive state of the avian ancestral Z chromosome. These results strongly suggest that the X and Y chromosomes of Staurotypus turtles are at a very early stage of sex chromosome differentiation, and that these chromosomes and the avian ZW chromosomes share the same origin. Nonetheless, the turtles and birds acquired different systems of heterogametic sex determination during their evolution. |
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Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 1 | 25% |
| Canada | 1 | 25% |
| Unknown | 2 | 50% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Scientists | 2 | 50% |
| Members of the public | 2 | 50% |
Mendeley readers
The data shown below were compiled from readership statistics for 48 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United Kingdom | 2 | 4% |
| Brazil | 1 | 2% |
| Australia | 1 | 2% |
| Czechia | 1 | 2% |
| Japan | 1 | 2% |
| Unknown | 42 | 88% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 9 | 19% |
| Student > Ph. D. Student | 8 | 17% |
| Student > Bachelor | 6 | 13% |
| Student > Master | 5 | 10% |
| Student > Doctoral Student | 3 | 6% |
| Other | 8 | 17% |
| Unknown | 9 | 19% |
| Readers by discipline | Count | As % |
|---|---|---|
| Agricultural and Biological Sciences | 24 | 50% |
| Biochemistry, Genetics and Molecular Biology | 8 | 17% |
| Computer Science | 3 | 6% |
| Environmental Science | 1 | 2% |
| Earth and Planetary Sciences | 1 | 2% |
| Other | 1 | 2% |
| Unknown | 10 | 21% |