Vargas-Ortiz Marcelo, Bobadilla Dante, Huanca-Mamani Wilson, Vargas Héctor A
a PPG Biologia Animal, Departamento de Zoologia , Instituto de Biociências, Universidade Federal do Rio Grande do Sul , Porto Alegre , Brazil.
b Departamento de Recursos Ambientales, Facultad de Ciencias Agronómicas , Universidad de Tarapacá , Arica , Chile.
Mitochondrial DNA A DNA Mapp Seq Anal. 2018 Dec;29(8):1139-1147. doi: 10.1080/24701394.2017.1419215. Epub 2017 Dec 22.
Analysis of maternally inherited genes is especially helpful in population studies of host-specialized insects, as female dispersal is key to find an adequate host plant to ensure larval survival. Bucculatrix mirnae (Lepidoptera: Bucculatricidae) is a little-known Neotropical micromoth native to the arid environments of northern Chile whose hypermetamorphic larvae are miners and skeletonizers on leaves of two species of Baccharis (Asteraceae) shrubs. This micromoth has been detected in three isolated locations embracing a narrow geographic range: two from the coastal valleys of the Atacama Desert near sea level and one from the western slopes of the Andes at about 3000 m elevation. As the dispersal of B. mirnae is mostly restricted to the small adult stage, the altitudinal gradient and desert areas among the three localities could be effective barriers, triggering genetic differentiation among populations. Sequences of the DNA barcode fragment of the cytocrome oxidase subunit I mitochondrial gene were analyzed to assess for the first time the patterns of genetic variation of B. mirnae. Fifteen haplotypes, each exclusive to one locality, were found in the 71 specimens analyzed. Genetic divergence (K2P) between haplotypes of different localities was at least 2.0%. A Bayesian analysis with sequences of congeneric species grouped all the B. mirnae haplotypes in a clade, in which three well-supported locality-specific haplogroups were found. In concordance with this pattern, an analysis of molecular variance showed that the highest genetic variation was found among populations. Furthermore, all the population pairwise comparisons (F) were significant. These results suggest that female migration between isolated populations of B. mirnae is absent. This pattern must be considered in the current scenario of habitat destruction and modification in the arid environments of northern Chile.
对母系遗传基因的分析在宿主专一性昆虫的种群研究中特别有用，因为雌性扩散是找到合适宿主植物以确保幼虫存活的关键。米氏布谷蛾（鳞翅目：布谷蛾科）是一种鲜为人知的新热带微蛾，原产于智利北部的干旱环境，其超变态幼虫是两种酒神菊属（菊科）灌木叶片的潜叶虫和食叶肉者。这种微蛾已在三个孤立地点被发现，地理范围狭窄：两个位于海平面附近阿塔卡马沙漠的沿海山谷，一个位于海拔约3000米的安第斯山西坡。由于米氏布谷蛾的扩散大多局限于成虫阶段，三个地点之间的海拔梯度和沙漠地区可能是有效的障碍，引发种群间的遗传分化。分析了细胞色素氧化酶亚基I线粒体基因的DNA条形码片段序列，首次评估了米氏布谷蛾的遗传变异模式。在分析的71个标本中发现了15个单倍型，每个单倍型都只存在于一个地点。不同地点单倍型之间的遗传距离（K2P）至少为2.0%。对同属物种序列进行的贝叶斯分析将所有米氏布谷蛾单倍型归为一个进化枝，其中发现了三个得到充分支持的地点特异性单倍群。与此模式一致，分子方差分析表明，种群间的遗传变异最高。此外，所有种群间的成对比较（F）均具有显著性。这些结果表明，米氏布谷蛾孤立种群之间不存在雌性迁移。在智利北部干旱环境目前的栖息地破坏和改变的情况下，必须考虑这种模式。
