Mapfile and ASV table of whole-body and shell-surface samples from geminate species of gastropods separated by the Isthmus of Panama

The rise of the Isthmus of Panama ~3.5 mya separated populations of many
marine organisms, which then diverged into new geminate sister species
currently living in the Eastern Pacific Ocean and Caribbean Sea. However,
we know very little about how such evolutionary divergences of host
species have shaped their microbiomes. Here, we compared the microbiomes
of whole-body and shell-surface samples of geminate species of marine
gastropods in the
genera Cerithiumand Cerithideopsis to those of
congeneric outgroups. Our results show that the effects of the Isthmus on
microbiome composition varied among host genera and between sample types
within the same hosts. In the whole-body samples, microbiome compositions
of geminate species pairs in the focal genera tended to be similar, likely
due to host filtering, although the strength of this relationship varied
among the two groups and across similarity metrics. Shell-surface
communities showed contrasting patterns, with co-divergence between the
host taxa and a small number of microbial clades evident
in Cerithideopsis, but not Cerithium. These results
suggest that (i) the rise of the Isthmus of Panama affected microbiomes of
geminate hosts in a complex and clade-specific manner and (ii)
host-associated microbial taxa respond differently to vicariance events
than the hosts themselves.

约350万年前巴拿马地峡（Isthmus of Panama）的抬升，分隔了诸多海洋生物种群，这些种群随后分化为目前分别栖息于东太平洋与加勒比海的成对姊妹物种（geminate sister species）。然而，我们对宿主物种的这类演化分化如何塑造其微生物组（microbiome）仍知之甚少。本研究对蟹守螺属（Cerithium）与拟蟹守螺属（Cerithideopsis）的成对姊妹海洋腹足类（marine gastropods）物种的全身体样本及壳表样本的微生物组，与同属外群（congeneric outgroups）样本进行了对比分析。结果显示，巴拿马地峡对微生物组组成的影响因宿主类群而异，且同一宿主的不同样本类型间也存在差异。在全身体样本中，目标属的成对姊妹物种的微生物组组成往往较为相似，这可能源于宿主的过滤作用，不过该关联的强度在两个类群间及不同相似性度量标准下均存在差异。壳表群落则呈现出相反的模式：拟蟹守螺属中可见宿主类群与少量微生物演化支的共分化（co-divergence）现象，但蟹守螺属中并无此特征。上述结果表明：其一，巴拿马地峡的抬升以复杂且类群特异性的方式影响了成对姊妹宿主的微生物组；其二，与宿主自身相比，宿主相关的微生物类群对隔离事件（vicariance events）的响应模式存在差异。