<p>Is it a boy or a girl? For baby sea turtles it is not that cut and dry as their sex is defined during development by the incubation environment, a new study has found.<br /><br />Baby sea turtles do not have an X or Y chromosome. The nest's thermal environment determines whether an embryo will develop as a male or female.<br /><br />Warmer sand temperatures produce more females and cooler sand temperatures produce more males, researchers from Florida Atlantic University in the US said.<br /><br />With the increase of global temperatures and climate change, sea turtle nests tend to produce more female-biased sex ratios further increasing their risk of extinction.<br /><br />Despite this risk, very few studies actually verify the sex of individual sea turtles and then compare that data to predictions of sex ratios based on the incubation environment.<br /><br />A crucial step in the conservation of these animals is estimating hatchling sex ratios, which remains imprecise because of their anatomical makeup, researchers said.<br /><br />Scientists rely mainly upon laparoscopic procedures to verify neonate turtle sex. However, in some species, anatomical sex can be ambiguous even down to the histological level.<br /><br />Researchers modified an immunohistochemical (IHC) approach used in freshwater turtles and tested its accuracy in identifying the sex in hatchling loggerhead and leatherback turtles.<br /><br />They hypothesised that CIRPB - a RNA-binding protein known to respond to temperature - may show differential gene expression in marine turtle hatchlings that are both well-differentiated and those that are not yet distinctly male or female.<br /><br />To assess the utility of this new approach, they successfully tested the expression of CIRPB using IHC with loggerhead turtle hatchlings and post-hatchlings samples because that species' sex can be identified reliably via laparoscopy and standard histology.<br /><br />Results showed a 93 per cent success agreement between the IHC method and the established sex-identification techniques for loggerhead turtles.<br /><br />They then used the technique with leatherback turtles and got a 100 per cent agreement between the IHC method and established sex-identification techniques.<br /><br />"The high level of CIRPB expression found in the developing ovaries of marine turtle hatchlings and post-hatchlings also supports our hypothesis that CIRBP may play a role in the molecular pathways of sexual differentiation in marine turtles," said Boris M Tezak, FAU graduate student. The study was published in The Anatomical Record journal.</p>
<p>Is it a boy or a girl? For baby sea turtles it is not that cut and dry as their sex is defined during development by the incubation environment, a new study has found.<br /><br />Baby sea turtles do not have an X or Y chromosome. The nest's thermal environment determines whether an embryo will develop as a male or female.<br /><br />Warmer sand temperatures produce more females and cooler sand temperatures produce more males, researchers from Florida Atlantic University in the US said.<br /><br />With the increase of global temperatures and climate change, sea turtle nests tend to produce more female-biased sex ratios further increasing their risk of extinction.<br /><br />Despite this risk, very few studies actually verify the sex of individual sea turtles and then compare that data to predictions of sex ratios based on the incubation environment.<br /><br />A crucial step in the conservation of these animals is estimating hatchling sex ratios, which remains imprecise because of their anatomical makeup, researchers said.<br /><br />Scientists rely mainly upon laparoscopic procedures to verify neonate turtle sex. However, in some species, anatomical sex can be ambiguous even down to the histological level.<br /><br />Researchers modified an immunohistochemical (IHC) approach used in freshwater turtles and tested its accuracy in identifying the sex in hatchling loggerhead and leatherback turtles.<br /><br />They hypothesised that CIRPB - a RNA-binding protein known to respond to temperature - may show differential gene expression in marine turtle hatchlings that are both well-differentiated and those that are not yet distinctly male or female.<br /><br />To assess the utility of this new approach, they successfully tested the expression of CIRPB using IHC with loggerhead turtle hatchlings and post-hatchlings samples because that species' sex can be identified reliably via laparoscopy and standard histology.<br /><br />Results showed a 93 per cent success agreement between the IHC method and the established sex-identification techniques for loggerhead turtles.<br /><br />They then used the technique with leatherback turtles and got a 100 per cent agreement between the IHC method and established sex-identification techniques.<br /><br />"The high level of CIRPB expression found in the developing ovaries of marine turtle hatchlings and post-hatchlings also supports our hypothesis that CIRBP may play a role in the molecular pathways of sexual differentiation in marine turtles," said Boris M Tezak, FAU graduate student. The study was published in The Anatomical Record journal.</p>