Voila:
http://www.pnas.org/content/103/17/6581 Το λέει και στον τίτλο (Morphologic and molecular
evolution of bat wing digits) και στο κείμενο, όπου εξηγεί το πώς η αλλαγή στη έκφραση ενός γονιδίου οδήγησε στην μορφολογική
εξέλιξη των νυχτερίδων: "...Together, our results indicate the up-regulation of the Bmp pathway as a major and fundamental (although not necessarily the only) mechanism responsible for the
developmental elongation of bat forelimb digits. Based on our results, we raise the intriguing possibility that a similar up-regulation of the Bmp pathway had a role in the
evolutionary elongation of bat forelimb digits, which is an event that was critical to the achievement of powered flight in bats. Recent studies (22, 23) have suggested that modifications to the cis-regulatory elements of developmental genes have central roles in the
evolutionary diversification of morphology. Our evidence that Bmp2, but not Bmp4 or Bmp7, is differentially expressed in the bat wing digits is suggestive of a cis-regulatory change that affects the level, but not the temporal or spatial regulation, of Bmp2 expression. By linking a simple change in a single developmental pathway to dramatically different morphologies, we provide a potential explanation as to how bats were able to achieve powered flight soon after they
diverged from other mammals nearly 65 million years ago (2, 9).
Σχετικά με τα cis-regulatory elements: "CREs have an important
evolutionary role. The coding regions of genes are often well conserved among organisms; yet different organisms display marked phenotypic diversity. It has been found that polymorphisms occurring within non-coding sequences have a
profound effect on phenotype by altering gene expression.[3] Mutations arising within a CRE can generate expression variance by changing the way TFs bind. Tighter or looser binding of regulatory proteins will lead to up- or down-regulated transcription.
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