The birth of aposematism: High phenotypic divergence and low genetic diversity in a young clade of poison frogs
The birth of aposematism: High phenotypic divergence and low genetic diversity in a young clade of poison frogs
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警戒主义的诞生：年轻毒蛙进化枝的高表型分化和低遗传多样性
DOI：
10.1016/j.ympev.2016.12.035
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发表时间：
2017
影响因子：
4.1
通讯作者：
Cannatella, David C.
中科院分区：
文献类型：
--
作者：
Tarvin, Rebecca D.;Powell, Emily A.;Santos, Juan C.;Ron, Santiago R.;Cannatella, David C.
快速的辐射加上低的遗传分化往往会阻碍物种界定和生殖估计，即使假定的物种是表型不同。一些警戒性物种，如毒蛙（树蛙科），具有高水平的种内颜色多态性，这可能导致高估的物种时，表型分歧主要指导物种划界。我们探讨了这种可能性，在最年轻的起源aposematism（3-7 MYA）的毒蛙，Epipedobates，通过比较遗传分歧与颜色和声分歧。尽管颜色和声音信号存在显着差异，但我们发现遗传差异较低（16 Sgene为2.6%）。虽然化学防御被推断在Epipedobates的祖先中已经进化，但警戒色在Epipedobates中至少进化了两次或丢失了一次，这表明它是进化不稳定的。布兰格兰E. machalilla）。我们还发现外周隔离导致表型分化和潜在的物种形成的aposematicE的证据。三色非警戒色E。machalilla。然而，我们无法估计一个良好的支持物种树或划定物种使用多物种合并模型。我们将这一失败归因于与最近物种形成相关的因素，包括线粒体基因渗入、不完整的谱系分选和信息量太少的分子特征。我们认为，在年轻的aposematic谱系，如epipedobates物种划界将需要基因组水平的分子研究。我们告诫不要仅仅依靠DNA条形码来进行物种界定或鉴定，并强调表型差异和自然历史在界定物种方面的价值。
Rapid radiation coupled with low genetic divergence often hinders species delimitation and phylogeny estimation even if putative species are phenotypically distinct. Some aposematic species, such as poison frogs (Dendrobatidae), have high levels of intraspecific color polymorphism, which can lead to overestimation of species when phenotypic divergence primarily guides species delimitation. We explored this possibility in the youngest origin of aposematism (3–7 MYA) in poison frogs,Epipedobates, by comparing genetic divergence with color and acoustic divergence. We found low genetic divergence (2.6% in the16Sgene) despite substantial differences in color and acoustic signals. While chemical defense is inferred to have evolved in the ancestor ofEpipedobates, aposematic coloration evolved at least twice or was lost once inEpipedobates, suggesting that it is evolutionarily labile.We inferred at least one event of introgression between two cryptically colored species with adjacent ranges (E. boulengeriandE. machalilla). We also find evidence for peripheral isolation resulting in phenotypic divergence and potential speciation of the aposematicE. tricolorfrom the non-aposematicE. machalilla. However, we were unable to estimate a well-supported species tree or delimit species using multispecies coalescent models. We attribute this failure to factors associated with recent speciation including mitochondrial introgression, incomplete lineage sorting, and too few informative molecular characters. We suggest that species delimitation within young aposematic lineages such asEpipedobateswill require genome-level molecular studies. We caution against relying solely on DNA barcoding for species delimitation or identification and highlight the value of phenotypic divergence and natural history in delimiting species.