According to a recent study conducted at Duke University, it has been discovered that warmer temperatures not only result in a higher proportion of female turtle hatchlings but also enhance the reproductive capabilities of these female turtles. The research indicates that elevated incubation temperatures lead to an increased number of “germ cells” in turtle embryos, which are precursors to eggs and play a role in determining the sex of the turtle. This finding provides insights into the evolutionary significance of temperature-dependent sex determination and raises concerns about the potential consequences for these species in the face of climate change.
The study, published in the journal Current Biology on June 23, sheds light on the mechanisms behind temperature-dependent sex determination in turtles. It reveals that higher incubation temperatures stimulate the production of more germ cells in the embryos. Interestingly, these germ cells themselves contribute to the development of female turtles.
According to senior author Blanche Capel, the James B. Duke Distinguished Professor of Cell Biology at Duke School of Medicine, temperature-based sex determination is not solely reliant on a single mechanism. Instead, higher temperatures seem to influence sex determination incrementally through multiple cell types in the embryo.
Boris Tezak, a postdoctoral researcher in the Capel lab who led the project, explains that the abundance of germ cells is a driving factor in feminization. He states that the temperatures which produce female turtles also lead to an increased number of germ cells.
This connection between germ cell quantity and female development is also observed in fish. To further confirm the link between germ cells and female turtles, the researchers conducted an experiment where they removed some germ cells from red-eared slider embryos incubated at an intermediate temperature, which should have resulted in an equal number of males and females. However, they found a higher number of males than expected, supporting the hypothesis that more germ cells contribute to the development of female turtles.
Temperature-dependent sex determination has been observed in various species, not just turtles. It is considered a risky reproductive strategy that has nevertheless evolved multiple times in different organisms. The researchers propose that this persistence is due to the reproductive advantage it confers.
Tezak suggests that a female turtle hatched with a higher number of germ cells would likely be more reproductively fit, as it increases her potential to produce more eggs. Linking the female pathway to an increased number of germ cells provides a compelling explanation for the persistence of temperature-dependent sex determination.
As global temperatures continue to rise, the implications for temperature-sensitive species, including turtles, become a pressing concern. Tezak is currently studying how further temperature increases affect the pool of germ cells. The researchers are nurturing clutches of red-eared slider eggs at different temperatures to monitor their progress and determine the impact on germ cell development.
The team is also preparing to conduct temperature experiments using alligator eggs. Alligators exhibit the opposite pattern of sex determination compared to red-eared slider turtles, producing females at lower temperatures and males at higher temperatures. The researchers are curious to see if both species show an increase in germ cell quantity at the optimal temperature for female production.
In conclusion, this study provides valuable insights into the influence of temperature on turtle sex determination. The findings demonstrate the relationship between incubation temperature, germ cell numbers, and the development of female turtles. With the ongoing rise in global temperatures, understanding the implications of temperature-dependent sex determination is crucial for the conservation and management of temperature-sensitive species. The study was funded by the U.S. National Science Foundation and the Czech Science Foundation.
Reference: “Higher temperatures directly increase germ cell number, promoting feminization of red-eared slider turtles” by B. Tezak, B. Straková, D.J. Fullard, S. Dupont, J. McKey, C. Weber, and B. Capel, 23 June 2023, Current Biology. DOI: 10.1016/j.cub.2023.06.008.
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Frequently Asked Questions (FAQs) about turtle sex determination
What did the study from Duke University reveal about turtle sex determination?
The study revealed that warmer temperatures influence turtle sex determination, resulting in a higher proportion of female hatchlings and enhancing their reproductive capabilities. It also found that higher incubation temperatures increase the number of “germ cells” in turtle embryos, which play a role in determining the sex of the turtles.
Why is temperature-dependent sex determination considered a risky reproductive strategy?
Temperature-dependent sex determination is considered risky because it relies on external environmental factors, specifically temperature, to determine the sex of offspring. This strategy becomes precarious in the context of weather variations and climate change, where temperature fluctuations can disrupt the balance between male and female ratios in a population.
How do higher numbers of germ cells affect female turtle development?
Higher numbers of germ cells in female turtle embryos contribute to feminization. The study found that the temperatures that produce females also lead to an increased number of germ cells. This suggests that more germ cells result in a higher likelihood of developing as a female turtle.
What is the potential impact of global warming on temperature-sensitive breeders like turtles?
As global temperatures continue to rise, there are concerns about the implications for temperature-sensitive breeders like turtles. The study raises questions about how further increases in temperature may affect the pool of germ cells and the fitness of females. It highlights the need to understand and mitigate the effects of climate change on these species for their long-term survival.
How does the study contribute to understanding temperature-dependent sex determination in other species?
The study provides valuable insights into the mechanisms and evolutionary significance of temperature-dependent sex determination, not just in turtles but also in other species. By demonstrating the relationship between incubation temperature, germ cell numbers, and female development, it sheds light on the broader phenomenon observed across various organisms and helps explain why this reproductive strategy persists in nature.
More about turtle sex determination
- Duke University Study on Turtle Sex Determination
- Current Biology Journal Article: “Higher temperatures directly increase germ cell number, promoting feminization of red-eared slider turtles”
- U.S. National Science Foundation
- Czech Science Foundation
5 comments
So cool! Warmer temps make more germ cells which make more females! Lots of species have this weird sex thing! climate change = big problem!
Woah, warmer temps = more baby girl turtles! But what happens if it gets too hot? We need to stop global warming! Save the turtles!
This study is crucial for understanding how climate change affects wildlife. Temperature impacts turtle sex determination! We must take action to preserve their habitats.
Interesting findings! More germ cells mean more lady turtles. But will climate change mess it all up? We need to protect these cute creatures!
wow, this study from duke uni is amazing! it shows how temp affects turtle sex! more females, more eggs! climate change is scary tho 🙁