Protopterus aethiopicus, genome size, and protein differences

[Genecks]

As I think about Protopterus aethiopicus, I think that maybe while undergoing its evolution and possible genome size increases through that evolution... that maybe it picked up characteristics of making proteins that other species in the world don't. Perhaps it has certain anatomical and physiological characteristics that other animals do not, and those aspects may be locked up in its genome (perhaps unexpressed).

 

Are these things a possibility? Am I giving the the Protopterus aethiopicus too much credit for having such a large genome while still being able to live?

[Greippi]

There's not actually much literature on that specific species - there is a lot on its physiology but genome data is lacking. All we can do is speculate really.

What I have been able to dig up using Web of Science (hopefully you institution has access to it) shows that is has many proteins related to other fish (quite a large number of different species) and has homologues with human proteins. Perhaps the fact that it's the closest living relative to land vertebrates is the key to its large genome.

 

Perhaps the majority of the genome is so called 'junk DNA' involved in transcriptional control and such, as opposed to making novel proteins. In fact, there are quite a few papers on the metabolism and respiration of this fish - possibly the metabolism is under tight control or is very adaptive, which would require a large amount of regulatory genes.

 

Couple of sources I found:

Evolution of tissue-specific keratins as deduced from novel cDNA sequences of the lungfish Protopterus aethiopicus

Schaffeld M, Bremer M, Hunzinger C, Markl E 2005

EUROPEAN JOURNAL OF CELL BIOLOGY Volume: 84 Issue: 2-3 Pages: 363-377

 

I couldn't access this paper myself, but perhaps Protopterus aethiopicus has undergone wasteful strategy of evolution as described here:

Cell size and the concept of wasteful and frugal evolutionary strategies. Henryk Szarski. Journal of Theoretical Biology. Volume 105, Issue 2, 1983, Pages 201-209