Miklós Máté, Laczkó Levente, Sramkó Gábor, Barta Zoltán, Tökölyi Jácint
MTA-DE "Momentum" Ecology, Evolution and Developmental Biology Research Group, Department of Evolutionary Zoology University of Debrecen Debrecen Hungary.
Juhász-Nagy Pál Doctoral School of Biology and Environmental Sciences University of Debrecen Debrecen Hungary.
Ecol Evol. 2022 Jul 14;12(7):e9096. doi: 10.1002/ece3.9096. eCollection 2022 Jul.
Facultative sexual organisms combine sexual and asexual reproduction within a single life cycle, often switching between reproductive modes depending on environmental conditions. These organisms frequently inhabit variable seasonal environments, where favorable periods alternate with unfavorable periods, generating temporally varying selection pressures that strongly influence life history decisions and hence population dynamics. Due to the rapidly accelerating changes in our global environment today, understanding the population dynamics and genetic changes in facultative sexual populations inhabiting seasonal environments is critical to assess and prepare for additional challenges that will affect such ecosystems. In this study, we aimed at obtaining insights into the seasonal population dynamics of the facultative sexual freshwater cnidarian through a combination of restriction site-associated sequencing (RAD-Seq) genotyping and the collection of phenotypic data on the reproductive strategy of field-collected hydra strains in a standard laboratory environment. We reliably detected 42 MlGs from the 121 collected hydra strains. Most of MLGs ( = 35, 83.3%) were detected in only one season. Five MLGs (11.9%) were detected in two seasons, one (2.4%) in three seasons and one (2.4%) in all four seasons. We found no significant genetic change during the 2 years in the study population. Clone lines were detected between seasons and even years, suggesting that clonal lineages can persist for a long time in a natural population. We also found that distinct genotypes differ in sexual reproduction frequency, but these differences did not affect whether genotypes reappeared across samplings. Our study provides key insights into the biology of natural hydra populations, while also contributing to understanding the population biology of facultative sexual species inhabiting freshwater ecosystems.
兼性有性生物在单一生命周期内结合了有性和无性繁殖，通常会根据环境条件在繁殖模式之间切换。这些生物经常栖息在多变的季节性环境中，有利时期与不利时期交替出现，产生随时间变化的选择压力，强烈影响生活史决策，进而影响种群动态。由于当今全球环境变化迅速加速，了解栖息在季节性环境中的兼性有性种群的种群动态和遗传变化对于评估和应对将影响此类生态系统的额外挑战至关重要。在本研究中，我们旨在通过限制性位点相关测序（RAD-Seq）基因分型以及在标准实验室环境中收集野外采集的水螅菌株繁殖策略的表型数据，来深入了解兼性有性淡水刺胞动物的季节性种群动态。我们从121株采集的水螅菌株中可靠地检测到了42个多基因座基因型（MLGs）。大多数MLGs（n = 35，83.3%）仅在一个季节中被检测到。五个MLGs（11.9%）在两个季节中被检测到，一个（2.4%）在三个季节中被检测到，一个（2.4%）在所有四个季节中都被检测到。我们发现研究种群在两年内没有显著的遗传变化。在不同季节甚至不同年份之间都检测到了克隆系，这表明克隆谱系可以在自然种群中持续很长时间。我们还发现不同的基因型在有性繁殖频率上存在差异，但这些差异并不影响基因型在不同采样中是否再次出现。我们的研究为天然水螅种群的生物学提供了关键见解，同时也有助于理解栖息在淡水生态系统中的兼性有性物种的种群生物学。
