Malagasy shrew tenrecs (Microgale) have increasingly been used to study speciation genetics over the last years. A previous study recently uncovered gene flow between the Shrew-toothed shrew tenrec (M. soricoides) and sympatric southern population of the Pale shrew tenrec (M. fotsifotsy). This gene flow has been suggested to be accompanied by complete mitochondrial replacement in M. fotsifotsy. To explore the temporal framework of this replacement, we assembled mitogenomes from publicly available sequencing data of ultra-conserved elements. We were able to assemble complete and partial mitogenomes for 19 specimens from five species of shrew tenrecs, which represents a multifold increase in mitogenomic resources available for all tenrecs. Phylogenetic inferences and sequence simulations support the close relationship between the mitochondrial lineages of M. soricoides and the southern population of M. fotsifotsy. Based on the nuclear divergence of northern and southern populations of M. fotsifotsy and the mitochondrial divergence between the latter and M. soricoides, there was a mean time window for replacement of ~ 350,000 years. This timeframe implies that the effective size of the ancestral M. fotsifotsy southern population was less 70,000.

在过去的几年里，马达加斯加鼩鼱（Microgale ）越来越多地被用于研究物种形成遗传学。先前的一项研究最近揭示了鼩齿鼩鼩 ( M. soricoides ) 和淡鼩鼩鼩 ( M. fotsifotsy) 的同域南部种群之间的基因流动。这种基因流动被认为伴随着M. fotsifotsy中的完全线粒体替代. 为了探索这种替换的时间框架，我们从公开可用的超保守元素测序数据中组装了有丝分裂基因组。我们能够为来自五种鼩鼱鼩鼱的 19 个标本组装完整和部分的有丝分裂基因组，这代表了所有鼩鼱可用的有丝分裂基因组资源的多倍增加。系统发育推断和序列模拟支持 M. soricoides 线粒体谱系与M. fotsifotsy南方种群之间的密切关系。基于 M. fotsifotsy 北部和南部种群的核分歧以及后者与M. soricoides之间的线粒体分歧，更换的平均时间窗口约为 350,000 年。这个时间范围意味着祖先M. fotsifotsy南方人口的有效规模少于 70,000。