Department of Genetics, Universidade Federal do Rio Grande do Sul, PoBox 15053, Porto Alegre, 91501-970, Brazil.
Sci Rep. 2024 Feb 15;14(1):3825. doi: 10.1038/s41598-024-53414-4.
Phylogeographic history refers to how species evolve and diversify in response to historical, ecological, and demographic factors. The climate fluctuation during the Pleistocene period marked a crucial time in shaping many species' distribution and genetic structure, particularly those from southern South American grasslands. This work investigated the phylogeographic history of a highland grassland, Petunia altiplana T. Ando & Hashim. (Solanaceae), its diversity, and geographic distribution using a population genomic approach based on RAD-seq data. Our results indicated that, during the Pleistocene, when the grasslands expanded to highlands, the lowland populations of P. altiplana reached the higher open fields, enlarging their geographic distribution. We found that the P. altiplana genetic diversity followed the geographic division into eastern (E) and western (WE) population groups, with a subtle division in the E group regarding the Pelotas River headwater. The results also showed that isolation by distance was the main divergence pattern, with elevation playing a pivotal role in shaping WE and E groups. Our findings indicated that lowland-adapted populations quickly colonized highlands during the late Pleistocene.
系统发育地理历史是指物种如何响应历史、生态和人口因素而进化和多样化。更新世期间的气候波动是许多物种分布和遗传结构形成的关键时期，特别是来自南美南部草原的物种。本研究采用基于 RAD-seq 数据的群体基因组学方法，研究了高山草原矮牵牛（Petunia altiplana T. Ando & Hashim.）的系统发育地理历史、多样性和地理分布。研究结果表明，在更新世期间，当草原扩展到高海拔地区时，矮牵牛的低地种群到达了更高的开阔地，扩大了其地理分布。我们发现，矮牵牛的遗传多样性遵循东部（E）和西部（WE）种群群体的地理划分，E 群体在 Pelotas 河源附近存在细微的划分。结果还表明，隔离距离是主要的分化模式，海拔对 WE 和 E 群体的形成起着关键作用。研究结果表明，适应低地的种群在更新世晚期迅速向高海拔地区殖民。
