Schnitzler Carolina K, Turchetto Caroline, Teixeira Marcelo C, Freitas Loreta B
Universidade Federal do Rio Grande do Sul, Departamento de Genética, Laboratório de Evolução Molecular, Porto Alegre, RS, Brazil.
Genet Mol Biol. 2020 Jun 3;43(2):e20190271. doi: 10.1590/1678-4685-GMB-2019-0271. eCollection 2020.
Interspecific hybridization has been fundamental in plant evolution. Nevertheless, the fate of hybrid zones throughout the generations remains poorly addressed. We analyzed a pair of recently diverged, interfertile, and sympatric Petunia species to ask what fate the interspecific hybrid population has met over time. We analyzed the genetic diversity in two generations from two contact sites and evaluated the effect of introgression. To do this, we collected all adult plants from the contact zones, including canonicals and intermediary colored individuals, and compared them with purebred representatives of both species based on seven highly informative microsatellite loci. We compared the genetic diversity observed in the contact zones with what is seen in isolated populations of each species, considering two generations of these annual species. Our results have confirmed the genetic differentiation between the species and the hybrid origin of the majority of the intermediary colored individuals. We also observed a differentiation related to genetic variability and inbreeding levels among the populations. Over time, there were no significant differences per site related to genetic diversity or phenotype composition. We found two stable populations kept by high inbreeding and backcross rates that influence the genetic diversity of their parental species through introgression.
种间杂交在植物进化中起着基础性作用。然而，杂交区域在几代中的命运仍未得到充分研究。我们分析了一对最近分化、可育且同域分布的矮牵牛属物种，以探究种间杂交种群随时间推移的命运。我们分析了来自两个接触位点的两代个体的遗传多样性，并评估了基因渐渗的影响。为此，我们收集了接触区域的所有成年植株，包括典型个体和中间色个体，并基于七个高度信息丰富的微卫星位点，将它们与两个物种的纯种代表进行比较。考虑到这两个一年生物种的两代个体，我们将在接触区域观察到的遗传多样性与每个物种孤立种群中的遗传多样性进行了比较。我们的结果证实了物种之间的遗传分化以及大多数中间色个体的杂交起源。我们还观察到种群之间在遗传变异性和近亲繁殖水平方面的差异。随着时间的推移，每个位点在遗传多样性或表型组成方面没有显著差异。我们发现有两个稳定的种群，其近亲繁殖和回交率很高，通过基因渐渗影响其亲本物种的遗传多样性。
