Tempo and Mode of Genome Evolution 50 000 Generation Experiment Discussion

This forum is for students that will be summarizing the Tenaillon et al. 2016 paper.

To get full participation credit, you must post at least once and respond to at least 2 posts from your classmates.

Here’s response 1 Wendy Yang

Confusion with tree diagram

COLLAPSE

I’m confused about the numbers of the phylogenetic tree. What does the numbers represent? On the red panda branch there shows +779/-4693, what does the numbers mean.

I found that it was interesting was that both red pandas and great pandas developed pseudothumbs. Changes to the DYNC2H1 and PCNT resulted in alternation in limb development. Since both species almost exclusively consume bambooa thumb would greatly help them grasp on to the food; but why can’t this be a case of a hitchhiking gene? I know the development for a taste for bamboo was not because an ancestor of great panda did partially consume plants (e.g Ailuropoda Microta) which had a broader diet then the modern panda. They had cuspy teeth (which helps break down plant material). Is it not possible for the pseudothumb gene to be connected to eating bamboo? In addition which evolved first the umami taste receptor or the the pseudotumb? 

Erica Reven

Pseudogenes

COLLAPSE

I found it interesting that, unlike the other means of convergent evolution (amino acid sequence changes that resulted in more efficient genes), the genes for umami taste receptors, and 9 other shared genes, experienced deletions and insertions that resulted in them becoming pseudogenes. In my research of pseudogenes, I found that they are usually detrimental to the organism and selectively disadvantageous, but in the case of the pandas, their reliance on bamboo as their only source of nutrition makes these pseudogenes actually highly advantageous and necessary to their survival. I wonder if the different means by which the TAS1R1 gene became a pseudogene matters in analysis of convergent evolution. In the red panda, the gene experienced a deletion in the 6th exon, and in the giant panda, the gene experienced 3 insertion/deletion mutations in the 3rd and 6th exons. Does convergent evolution require that the process by which two species converge be similar?