Repeated evolution of eye loss in Mexican cavefish: Evidence of similar developmental mechanisms in independently evolved populations
Repeated evolution of eye loss in Mexican cavefish: Evidence of similar developmental mechanisms in independently evolved populations
复制标题
墨西哥穴居鱼眼睛丧失的反复进化：独立进化种群中类似发育机制的证据
DOI：
10.1002/jez.b.22977
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Kowalko, Johanna E.
中科院分区：
文献类型：
--
作者：
Sifuentes‐Romero, Itzel;Ferrufino, Estephany;Thakur, Sunishka;Laboissonniere, Lauren A.;Solomon, Michael;Smith, Courtney L.;Keene, Alex C.;Trimarchi, Jeffrey M.;Kowalko, Johanna E.
相似环境下的进化往往导致行为和解剖特征的趋同。趋同特征进化的一个经典例子是许多洞穴动物特征的减少：色素沉着和眼睛的减少或丧失。虽然这些特征已经进化了很多次，但对于这些特征是否通过相同或不同的分子和发育机制反复进化，我们知之甚少。这种小型淡水鱼，墨西哥Astyanax mexicanus，为研究洞穴特征的反复进化提供了机会。墨西哥人以两种形式存在，一种是有视力的地表生活形式，另一种是至少29种失明的洞穴生活形式，最初发育眼睛，随后退化。我们比较了发育中的表层鱼和两个独立进化的洞穴鱼种群Pachón和Molino的眼睛形态和眼睛调节基因的表达。我们发现许多先前描述的在Pachón洞穴鱼眼睛发育过程中发生的分子和形态变化也在Molino洞穴鱼中发现。然而，在许多这些特征中，莫利诺洞穴鱼的表型没有Pachón洞穴鱼那么严重。此外，穴居杂交鱼在发育早期的眼睛和晶状体都比亲本鱼大，这表明在这两个种群中，一些不同的变化导致了眼睛的丧失。总之，这些数据支持了这样一个假设，即这两个洞穴鱼种群独立地进化出了视力丧失，但通过一些相同的发育和分子机制。
Evolution in similar environments often leads to convergence of behavioral and anatomical traits. A classic example of convergent trait evolution is the reduced traits that characterize many cave animals: reduction or loss of pigmentation and eyes. While these traits have evolved many times, relatively little is known about whether these traits repeatedly evolve through the same or different molecular and developmental mechanisms. The small freshwater fish,Astyanax mexicanus, provides an opportunity to investigate the repeated evolution of cave traits.A. mexicanusexists as two forms, a sighted, surface‐dwelling form and at least 29 populations of a blind, cave‐dwelling form that initially develops eyes that subsequently degenerate. We compared eye morphology and the expression of eye regulatory genes in developing surface fish and two independently evolved cavefish populations, Pachón and Molino. We found that many of the previously described molecular and morphological alterations that occur during eye development in Pachón cavefish are also found in Molino cavefish. However, for many of these traits, the Molino cavefish have a less severe phenotype than Pachón cavefish. Further, cave–cave hybrid fish have larger eyes and lenses during early development compared with fish from either parental population, suggesting that some different changes underlie eye loss in these two populations. Together, these data support the hypothesis that these two cavefish populations evolved eye loss independently, yet through some of the same developmental and molecular mechanisms.