Gainsford Ashton, Jones Geoffrey P, Hobbs Jean-Paul A, Heindler Franz Maximilian, van Herwerden Lynne
ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville QLD Australia.
Faculty of Science and Engineering James Cook University Townsville Australia Australia.
Ecol Evol. 2020 Oct 21;10(21):11998-12014. doi: 10.1002/ece3.6769. eCollection 2020 Nov.
Hybridization and introgression are evolutionarily significant phenomena breaking down species boundaries. "Hybrid zones" (regions of species overlap and hybridization) enable quantification of hybridization frequency and examination of mechanisms driving and maintaining gene flow. The hybrid anemonefish is found where parent species () distributions overlap. Here, we examine geographic variation in hybridization and introgression, and potential impacts on parent species integrity through assessing relative abundance, social group composition, and genetic structure (mtDNA cytochrome , 21 microsatellite loci) of taxa at three hybrid zone locations: Kimbe Bay (KB) and Kavieng (KA), Papua New Guinea; the Solomon Islands (SO). Relative abundances of and size disparities between parent species apparently drive hybridization frequency, introgression patterns, and genetic composition of taxa. Conspecific groups are most common in KB (65%) where parent species are similarly abundant. Conversely, mixed species groups dominate SO (82%), where is more abundant. Hybrids most commonly cohabit with in KB (17%), but with in KA (22%) and SO (50%). Genetic differentiation (nDNA) analyses indicate that parent species remain distinct, despite ongoing hybridization and hybrids are genetically similar to resulting from persistent backcrossing with this smallest species. This study shows that hybridization outcomes may depend on the social and ecological context in which taxa hybridize, where relative abundance and disparate size of parent species explain the frequency and patterns of hybridization and introgression in the hybrid zone, reflecting size-based dominance behaviors of anemonefish social groups.
杂交和基因渗入是具有进化意义的现象，它们打破了物种界限。“杂交带”（物种重叠和杂交的区域）能够量化杂交频率，并研究驱动和维持基因流动的机制。杂交小丑鱼出现在亲本物种（ ）分布重叠的区域。在这里，我们通过评估三个杂交带位置（巴布亚新几内亚的金贝湾（KB）和卡维恩（KA）；所罗门群岛（SO））的分类单元的相对丰度、社会群体组成和遗传结构（线粒体DNA细胞色素 ，21个微卫星位点），来研究杂交和基因渗入的地理变异，以及对亲本物种完整性的潜在影响。亲本物种之间的相对丰度和大小差异显然驱动着分类单元的杂交频率、基因渗入模式和遗传组成。同种群体在亲本物种数量相似的KB最为常见（65%）。相反，混合物种群体在 更为丰富的SO占主导（82%）。在KB，杂种最常与 同居（17%），但在KA为 （22%），在SO为 （50%）。遗传分化（核DNA）分析表明，尽管存在持续杂交，但亲本物种仍然保持 distinct，并且杂种在基因上与因与这个最小物种持续回交而产生的 相似。这项研究表明，杂交结果可能取决于分类单元杂交的社会和生态背景，亲本物种的相对丰度和大小差异解释了小丑鱼杂交带中杂交和基因渗入的频率和模式，反映了小丑鱼社会群体基于大小的优势行为。
