| derived x chromosome in the turtle genus staurotypus. | c-banding, g-banding, and silver (ag-as) staining techniques reveal a distinctive sex chromosome system in the turtle staurotypus salvinii. unlike previously described systems in most other vertebrate groups in which the y or w is derived and the homogametic sex represents the primitive condition, the reverse is true for s. salvinii. the x chromosome is derived; thus the homogametic sex (female) is more derived than the heterogametic sex. the male is intermediate between the female and the ances ... | 2000 | 92052 |
| the staurotypus turtles and aves share the same origin of sex chromosomes but evolved different types of heterogametic sex determination. | 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 ... | 2014 | 25121779 |
| long-term sex reversal by oestradiol in amniotes with heteromorphic sex chromosomes. | oestradiol application during embryonic development reverses the sex of male embryos and results in normal female differentiation in reptiles lacking heteromorphic sex chromosomes, but fails to do so in birds and mammals with heteromorphic sex chromosomes. it is not clear whether the evolution of heteromorphic sex chromosomes in amniotes is accompanied by insensitivity to oestradiol, or if the association between oestradiol insensitivity and heteromorphic sex chromosomes can be attributable to p ... | 2006 | 17148408 |