Genome Length

Timothy R Jackson tjackson at uoguelph.ca
Fri Oct 6 08:37:55 EST 1995


David Thornton (DRTHORNT at SCIENCE.uwaterloo.ca) wrote:
: 	Hey there

: 	I had an Idea . I was sitting in my mol cell bio lecture learning 
: about this paradox that shows that some creatures in the same class have 
: larger genomes than others.  I was thinking with all that "junk" DNA does 
: that make the creature better able to handle new conidtions. I mean might 
: all of that junk DNA be coding for genes that are "latent" (to be used in 
: time of need) or more aptly to have their effects expressed in time of need?

the salmonids are a good example of the rough idea that you're getting 
at.  about 25-100 million years ago their ancestor doubled their genome 
which gave rise to the family salmonidae (this is the same process that 
is thought to have given rise to the vertebrates).  their closest ancestor, 
the 
smelts, have half the genetic material of salmonids.  the salmonids are 
a highly diverse taxa with an extensive range, expoiting a wide variety 
of environments and exhibiting varying life history behaviours.  this may 
be a result of the "evolutionary potential" that an extra set of genes 
gave them.
tim



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