Subterranean mammals show convergent regression in ocular genes and enhancers, along with adaptation to tunneling

Autor: Ken K. Nischal, Joseph D. Robinson, Bharesh K. Chauhan, Zélia Ferreira, Maria Chikina, Raghavendran Partha, Kira L. Lathrop, Nathan L. Clark
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: eLife
eLife, Vol 6 (2017)
ISSN: 2050-084X
Popis: The underground environment imposes unique demands on life that have led subterranean species to evolve specialized traits, many of which evolved convergently. We studied convergence in evolutionary rate in subterranean mammals in order to associate phenotypic evolution with specific genetic regions. We identified a strong excess of vision- and skin-related genes that changed at accelerated rates in the subterranean environment due to relaxed constraint and adaptive evolution. We also demonstrate that ocular-specific transcriptional enhancers were convergently accelerated, whereas enhancers active outside the eye were not. Furthermore, several uncharacterized genes and regulatory sequences demonstrated convergence and thus constitute novel candidate sequences for congenital ocular disorders. The strong evidence of convergence in these species indicates that evolution in this environment is recurrent and predictable and can be used to gain insights into phenotype–genotype relationships.
eLife digest Over the past 100 million years, many mammals, such as moles or mole rats, for example, have evolved to live almost entirely underground. During their transition to adapt to life underground, many species have reduced or completely lost their sense of sight, and often have only a small remnant of an eye that can sometimes be completely covered by skin and fur. In addition, the sections of the DNA that usually control how the eyes form have changed in these animals. Since there is less need for a working eye in dark environments, DNA related to the eye is no longer protected from damaging mutations in mammals that live underground. So, by comparing the DNA of mammals that live aboveground and underground, scientists can identify the parts of DNA that help form mammals’ eyes. Previous studies have discovered many sections of DNA responsible for producing the proteins that make up the eye. However, scientists know less about which sections of DNA control when and where these proteins are made. To address this, Partha et al. have studied the DNA of four underground mammals: the star-nosed mole, the cape golden mole, the naked mole-rat and the blind mole-rat. By comparing the DNA of these animals with that of mammals that live above ground, Partha et al. identified sections of DNA that contained an abnormally high number of changes in the blind underground mammals. Many of these sections are involved in forming the eye, including controlling when and where proteins are made. Overall, the findings show that comparing rates of evolution in different species can help uncover sections of DNA that guide and influence how organisms develop. Understanding how the eye is formed is not only of interest to scientists studying evolution and biology; it also has wider applications in healthcare. Many people suffer from unexplained eye abnormalities, and insight into the sections of DNA that control the eye’s development could help medical professionals diagnose these cases and design new treatments.
Databáze: OpenAIRE
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