Corn snake genome sequenced for the first time

[Rich Z]

Date: November 24, 2015
Source: Université de Genève
Summary: Among the 5,000 existing species of mammals, more than 100 have their genome sequenced, whereas the genomes of only 9 species of reptiles (among 10,000 species) are available to the scientific community. This is the reason why a team of researchers has produced a large database including, among others, the newly-sequenced genome of the corn snake, a species increasingly used to understand the evolution of reptiles. Within the same laboratory, the researchers have discovered the exact mutation that causes albinism in that species.

Source: http://www.sciencedaily.com/releases/2015/11/151124081910.htm

 

[DollysMom]

Wonderful article and great news. Thanks!

 

[daddio207]

Great article !
Thanks for posting, Rich.

 

[NiklasTyreso]

Part of the good news is that cornsnakes are not neanderthal hybrids,
as we humans are.

 

[DuxorW]

The corn snake genome was actually sequenced a while back but this is in the news because the same group found the exact mutation that causes amelanism. It is the insertion of something called an LTR (long terminal repeat) retrotransposon. A retrotransposon is kind of like a genome parasite. They are in the DNA and encode enzymes that transcribe the retrotranspson into RNA, then reverse-transcribe this RNA back into DNA and insert it into the genome at a new location. When a retrotransposon inserts into an important region of a gene, it can disrupt that gene's function. In this case it interfered with RNA splicing and results in the protein product of the amel locus (now identified as OCA2) being truncated and nonfunctional.

Now that the amel mutation has been mapped to a specific locus, it should be trivial to sequence the ultra allele to determine why it is only partially functional relative to the wt allele.

 

[Zimmer]

That is amazing! I wish I understood the finer points here I will admit some of this is lost on me but very interesting!

 

[dave partington]

Date: November 24, 2015
Source: Université de Genève
Summary: Among the 5,000 existing species of mammals, more than 100 have their genome sequenced, whereas the genomes of only 9 species of reptiles (among 10,000 species) are available to the scientific community. This is the reason why a team of researchers has produced a large database including, among others, the newly-sequenced genome of the corn snake, a species increasingly used to understand the evolution of reptiles. Within the same laboratory, the researchers have discovered the exact mutation that causes albinism in that species.

Source: http://www.sciencedaily.com/releases/2015/11/151124081910.htm

So, did the researchers discover what causes albinism in a select group of captive bred cornsnakes,
or,
did the researchers discover what causes albinism in the original wild-collected amelanistic cornsnakes?

Because I've seen a messload of amel corn snakes, but i've never seen an albino cornsnake.

 

[DuxorW]

In their scientific journal article, they only use the term amelanistic when referring to snakes. But because albinism in humans is caused by lack of melanin in the eyes, hair, and/or skin, I can see why amelanistic reptiles are often referred to as albino.

The authors believe that this transposon insertion is the mutation that causes amelanism in all captive-bred amelanistic corn snakes (they identified the causal mutation using captive-bred corns) since they are presumed to have inherited their amel allele from the original wild-caught amels. However, amelanism has been found in wild corns in FL, TN, and NC, so who knows if the causal mutation is the same in all wild amel corns or if it is even in the same gene. But because (to my knowledge) nobody has ever bred two amel corns together and not gotten all amels, it is logical to assume that all captive-bred amels have the mutation identified in this paper and that they inherited it from their wild-caught ancestors.

The gene responsible also causes a type of albinism in humans when mutated.

The identification of this mutation would now allow us to determine with a PCR test whether a corn is het amel (not that this actually cost-effective). Thus possible het amels can be proven to be het amel without breeding. Further, if you know a corn has to be either het ultra or het amel, because one parent is an ultramel, it is now possible to determine which het they have. If they test negative for amel, they have to be het ultra.