2025-05-08 国立遺伝学研究所
<関連情報>
- https://www.nig.ac.jp/nig/ja/2025/05/research-highlights_ja/pr20250417.html
- https://www.nig.ac.jp/nig/images/research_highlights/PR20250417.pdf
- https://academic.oup.com/jeb/advance-article/doi/10.1093/jeb/voaf041/8114842
有性生殖の1つのエピソードが、二重のストレス要因のもとで個体群成長率に大きな変動をもたらすことがある A single episode of sexual reproduction can produce large variation in population growth rates under dual stressors
Yawako W Kawaguchi , Masato Yamamichi
Journal of Evolutionary Biology Published:17 April 2025
DOI:https://doi.org/10.1093/jeb/voaf041
Abstract
Sexual reproduction has been a central topic in evolutionary biology because of its many costs: why have organisms evolved sexual reproduction despite the many costs of sex? To answer the question, researchers have conducted laboratory experiments to measure population growth rates with and without sexual reproduction under a stressor. Here we show that a single episode of sexual reproduction can produce a large amount of variation in population growth rates under dual stressors by laboratory experiments of a green alga, Closterium peracerosum–strigosum–littorale complex. We observed population dynamics of the alga under dual stressors and confirmed that high salinity and low pH decreased growth rates. By comparing parental and their hybrid F1 populations, we observed larger variation in growth rates of F1 populations (i.e., transgressive segregation) when pH was low. Interestingly, even when parental populations had negative growth rates, some F1 populations showed positive growth rates in severe environmental conditions due to the large variation in population growth. By utilizing the recently obtained genomic information of the alga, we conducted a gene ontology (GO) enrichment analysis and found that genes with copy number variations between parental strains were more frequently associated with pH stress-related terms than salt stress-related terms. Our results suggest that recombination and variation in the number of gene copies might produce large genetic variation in the F1 generation. This will be an important step toward a better understanding of evolution of sex and evolutionary rescue where rapid contemporary evolution prevents population extinction in changing environments.
