Elucidating the genomic basis of adaptation and speciation is a major challenge in natural
systems with large quantities of environmental and phenotypic data, mostly because of the
scarcity of genomic resources for non-model organisms.
The Atlantic molly (Poecilia
mexicana, Poeciliidae) is a small livebearing fish that has been extensively studied for
evolutionary ecology research, particularly because this species has repeatedly colonized
extreme environments in the form of caves and toxic hydrogen sulfide containing springs.
In
such extreme environments, populations show strong patterns of adaptive trait divergence and
the emergence of reproductive isolation. Here, we used RNA-sequencing to assemble and annotate the first transcriptome of P. mexicana to facilitate ecological genomics studies in the
future and aid the identification of genes underlying adaptation and speciation in the system.
Description
We provide the first annotated reference transcriptome of P. mexicana. Our transcriptome
shows high congruence with other published fish transcriptomes, including that of the guppy,
medaka, zebrafish, and stickleback. Transcriptome annotation uncovered the presence of
candidate genes relevant in the study of adaptation to extreme environments.
We describe
general and oxidative stress response genes as well as genes involved in pathways induced by
hypoxia or involved in sulfide metabolism.
To facilitate future comparative analyses, we also
conducted quantitative comparisons between P. mexicana from different river drainages.
106,524 single nucleotide polymorphisms were detected in our dataset, including potential
markers that are putatively fixed across drainages.
Furthermore, specimens from different
drainages exhibited some consistent differences in gene regulation.
Conclusions
Our study provides a valuable genomic resource to study the molecular underpinnings of
adaptation to extreme environments in replicated sulfide spring and cave environments.
In
addition, this study adds to the increasing number of genomic resources in the family
Poeciliidae, which are widely used in comparative analyses of behavior, ecology, evolution,
and medical genetics.
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Further ReadingYou can view the full report and list of authors by clicking here. |
February 2013
