Navigation Links
Fish with temperature-dependent sex determination face global warming
Date:7/29/2008

In vertebrates with separate sexes, sex determination can be genotypic (GSD) or temperature-dependent (TSD). TSD is very common in reptiles, where the ambient temperature during sensitive periods of early development irreversibly determines whether an individual will be male or female. The number of males and females in a population is the sex ratio, a key demographic parameter crucial for population viability.

A number of previous studies have also suggested that TSD may also be very common in many species of fish, with increasing temperatures generally affecting the sex ratio of a species in one of three ways: increased numbers of males, increased numbers of females or increased numbers of males at high and low temperatures, with a balanced sex ratio at intermediate temperatures. However, to elicit a sex-ratio response to temperature, past experiments were often conducted only in the laboratory and not in the field, and the temperatures used were beyond the natural range of temperatures that the species experience in nature.

In a study directed by Francesc Piferrer, from the Institute of Marine Sciences in Barcelona, published in the open-access journal PLoS ONE on July 30, the Spanish researchers used field and laboratory data to critically analyze the presence of TSD in the 59 species of fish where this type of sex determining mechanism had been postulated.

The new study provides evidence that many cases where the observed sex ratio has shifted in response to temperature reveal thermal alterations of an otherwise predominately GSD mechanism rather than the presence of TSD. The results also show that in fish species with TSD, increasing temperatures invariably result in highly male-biased sex ratios. Finally, the researchers show that even small changes of just 1-2C can significantly alter the sex ratio from 1:1 (males:females) up to 3:1 in both freshwater and marine species.

This study shows that TSD in fish is far less widespread than currently believed, suggesting that TSD is clearly the exception in fish sex-determination. Thus, the scientists suggest that the evolution of sex-determining mechanisms in lower vertebrates, as is currently understood, needs to be revised. Further, species with TSD exhibit only one general change in sex ratio in response to temperature increase (leading to many males and few females). In many species, females determine the number of offspring for the next generation and so the viability of some fish populations with TSD can be compromised through alterations in their sex ratios due to temperature fluctuations of the magnitude predicted by climate change.

The researchers identify two key questions for future research. Firstly, whether the predicted effects can be observed in sensitive, natural populations there are indications that this could be the case in some populations of South American silversides. Secondly, while it is already known that high temperatures inhibit the synthesis of estrogens, which are essential for female sex differentiation in fish and reptiles, more work needs to be done into the molecular mechanism linking environmental temperature and estrogen synthesis.


'/>"/>

Contact: Francesc Piferrer
piferrer@icm.csic.es
Public Library of Science
Source:Eurekalert

Related biology news :

1. Researcher provides tool to enable determination of age of anchovies with greater precision
2. Quantitative PET imaging finds early determination of effectiveness of cancer treatment
3. A new explanation for evolutionary changes in genetic sex-determination systems
4. Paying to save tropical forests could be a way to reduce global carbon emissions
5. Durham scientists to tackle CO2 storage in global warming challenge
6. Global warming experts recommend drastic measures to save species
7. Pfizer inks global license to Genomatix Software and databases
8. Duckweed genome sequencing has global implications
9. Ancient oak trees help reduce global warming
10. Global Challenges/Chemistry Solutions debuts with focus on drinking water
11. Ecological globalization
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/22/2016)... , June 22, 2016   ... management and verification solutions, has partnered with ... software solutions for Visitor Management, Self-Service Kiosks ... provides products that add functional enhancements to ... provides corporations and venues with an automated ...
(Date:6/20/2016)... DALLAS , June 20, 2016 ... criminal justice technology solutions for public safety, investigation, ... by the prisons involved, it has secured the ... Corrections (DOC) facilities for Managed Access Systems (MAS) ... (4) additional facilities to be installed by October, ...
(Date:6/9/2016)... , June 9, 2016  Perkotek an innovation leader in attendance control systems is ... log work hours, for employers to make sure the right employees are actually signing ... http://photos.prnewswire.com/prnh/20160609/377486LOGO ... ... ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , June 27, 2016  Sequenom, Inc. (NASDAQ: ... enabling healthier lives through the development of innovative products ... the United States denied its ... the claims of Sequenom,s U.S. Patent No. 6,258,540 (",540 ... criteria established by the Supreme Court,s Mayo Collaborative Services ...
(Date:6/27/2016)... ... 27, 2016 , ... Newly created 4Sight Medical Solutions ... the healthcare market. The company's primary focus is on new product introductions, to ... that are necessary to help companies efficiently bring their products to market. , ...
(Date:6/27/2016)... June 27, 2016   Ginkgo Bioworks , a ... engineering, was today awarded as one of the ... the world,s most innovative companies. Ginkgo Bioworks is ... the real world in the nutrition, health and ... directly with customers including Fortune 500 companies to ...
(Date:6/24/2016)... ... 2016 , ... While the majority of commercial spectrophotometers and fluorometers use the ... models are higher end machines that use the more unconventional z-dimension of 20mm. ... the bottom of the cuvette holder. , FireflySci has developed several Agilent flow ...
Breaking Biology Technology: