Wings

[Patrick Foley]

There are genes that spread within a genome, they are known as 
transposons, essentially runaway scraps of feral DNA, not quite as 
self-sufficient as viruses. They are common, but probably mostly just 
elevate mutation rates when they jump into the wrong genes, or anooyingly 
expensive to reproduce when too many copies are made. Gene conversion is 
I believe a rare peculiarity.

The idea of orthogenesis is an old fuzzy one, that basically says that a 
line of organisms tends to continue to evolve in the same direction, 
perhaps even in the absence of natural selection. I can readily accept 
some versions of orthogenesis, but the less exciting concept of 
developmental constraints probably accounts for most of the phenomena 
called "orthogenesis".

Patrick Foley
patfoley at csus.edu