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:1/26/2017)... -- Acuity Market Intelligence today released the 2017 "Ten ... characterizes 2017 as a "breakout" year for biometrics ... new understanding of the potential benefits these technologies ... are often perceived as threats to privacy and ... Acuity Market intelligence. "However, taken together these technologies ...
(Date:1/21/2017)... , Jan 20, 2017 Research and ... Biometrics Market 2017-2021" report to their offering. ... The global voice recognition biometrics ... 2017-2021. The report covers the present scenario and ... 2017-2021. To calculate the market size, the report considers the revenue ...
(Date:1/13/2017)... PORT WASHINGTON, N.Y. , Jan. 13, 2017 ... provider of technology solutions for the homecare industry, ... appointment of homecare industry expert, Justin Jugs, as ... Justin brings more than 15 years of homecare ... the team in developing strategic plans to align ...
Breaking Biology News(10 mins):
(Date:2/17/2017)... , Feb. 17, 2017  If only ... tumor had a mutation-conferring resistance to chemotherapy, thousands ... genomics research has focused on finding these mutations ... even from circulating tumor DNA in blood — ... oncology therapeutics. Unfortunately, however, detecting these ...
(Date:2/16/2017)... ... February 16, 2017 , ... EIT Digital has launched ... the agricultural industry. Pilot studies are about to get under way for the framework, ... and 5G innovations. The concept is expected to be transferred eventually to other industries ...
(Date:2/16/2017)... GREENWICH, Conn. , Feb. 16, 2017 ... on venture growth investments in biotechnology and medical ... Richardson , M.D. to Managing Director. ... He is a board observer at InfaCare Pharmaceutical ... investments in Aimmune Therapeutics, Akebia Therapeutics, Cadence Pharmaceuticals ...
(Date:2/16/2017)... , Feb. 16, 2017 Research ... "Synthetic Biology: Global Markets" report to their offering. ... ... (synthetic genes, biobrick parts, delivery plasmids, chassis organisms, synthetic ... and assembly, genome editing, bioinformatics and specialty media) and ...
Breaking Biology Technology: