Data from: Limited usefulness of microsatellite markers from the malaria vector Anopheles gambiae when applied to the closely related species Anopheles melas

Anopheles melas is a brackish water mosquito found in coastal West Africa where it is a dominant malaria vector locally. In order to facilitate genetic studies of this species, 45 microsatellite loci originally developed for Anopheles gambiae were sequenced in An . melas. Those that were suitable based on repeat number and flanking regions were examined in 2 natural populations from Equatorial Guinea. Only 15 loci were eventually deemed suitable as polymorphic markers in An . melas populations. These loci were screened in 4 populations from a wider geographic range. Heterozygosity estimates ranged from 0.18 to 0.79, and 2.5–15 average alleles were observed per locus, yielding 13 highly polymorphic markers and 2 loci with lower variability. To examine the usefulness of microsatellite markers when applied in a sibling species, the original An . gambiae specific markers were used to amplify 5 loci in An . melas. Null alleles were found for 1 An . gambiae marker. We discuss the pitfalls of using microsatellite loci across closely related species and conclude that in addition to the problem of null alleles associated with this practice, many loci may prove to be of very limited use as polymorphic markers even when used in a sibling species.

咸水按蚊（Anopheles melas）是一种栖息于西非沿海咸水环境的蚊子，在当地为主要的疟疾传播媒介。为推动该物种的遗传学研究，研究人员对原本针对冈比亚按蚊（Anopheles gambiae）开发的45个微卫星位点（microsatellite loci）在咸水按蚊（An. melas）中进行了测序。筛选出那些基于重复序列数目与侧翼序列符合要求的位点后，研究人员在来自赤道几内亚的2个自然种群中开展了检测。最终仅确定15个位点可作为咸水按蚊种群中的多态性标记。随后，研究人员在覆盖更广地理范围的4个种群中对这些位点进行了筛查。杂合度估计值介于0.18至0.79之间，每个位点的平均等位基因数为2.5至15，最终得到13个高度多态性标记与2个变异程度较低的位点。为验证微卫星位点在姊妹种（sibling species）中的应用有效性，研究人员使用原本针对冈比亚按蚊开发的特异性标记，对咸水按蚊中的5个位点进行扩增。结果发现其中1个冈比亚按蚊标记存在无效等位基因（null alleles）。本文讨论了在近缘物种间使用微卫星位点的应用陷阱，并总结道：除该方法伴随的无效等位基因问题外，许多位点即便在姊妹种中使用，也可能被证实几乎无法作为多态性标记发挥作用。