Snake Species Essay

1152 Words 5 Pages
Throughout the course of the evolutionary history of species there are many morphological and phenotypical aspects of each species that either are common and shared, or a species diverges and new aspects can then be observed. One morphological feature that is observed in most fauna is the development of limbs; however, one species that is known to lack limb development is the snake species so that paper published by Kvon et al, investigates and tries to subside the debate over whether the sequence changes in non-coding regulatory DNA is the core driver of changes in the body shape in this species. In order to provide support for this dilemma, the researchers studied genomes of various snakes, both basal and advanced, to observe the evolutionary …show more content…
In Figure 1A, Kvon et al, showed a mouse embryo with human ZRS enhancer activity to express where in the embryo ZRS expression is located. To highlight the differences in the ZRS region and when they may have occurred evolutionarily, Figure 1B and 1C show a comparison in the ZRS region amongst the species and the phylogeny of these species, respectively, to better comprehend the progression of the loss of the limb enhancer. Through this it was found that the basal snakes ZRS enhancer was similar to limbed lizards and the substitution rate correlated with the other vertebrates, but the ZRS in the advanced snakes showed an increased number of substitutions compared to the other vertebrates. Overall every species of snakes has a ZRS enhancer and it was further exemplified that the separation between the basal and advanced snakes was based on the evolutionary constraint on the …show more content…
To determine how important this 17-bp deleted sequence is the researchers combined this sequence into the python enhancer sequence to see if the mouse model will then express limb development. This knockin experiment showed that the python enhancer with the 17-bp sequence showed normal limb development exemplifying that this sequence is a contributor to enhancer

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