Download Evoluce genomů

2009
EVOLUCE GENOMŮ
FOXP2
 = forkhead box 2
 mutation in this gene were found in families that have a high
incidence of abnormalities in speech and grammar
 only one aminoacid substitution had occured in the 130
Myr separating mice and ancestor of humans and
chimpanzees
 two substitution occured in the human lineage during
the 4-6 Myr since it separated from chimpanzees!
 this gene is virtually invariant in another 28 orders of
mammals that last shared common ancestor around
100 million years ago

(Futuyma, D.J., (2005) Evolution. Sinauer Associates, INC. Sunderland, MA,USA. p. 455)
MYH
 = sarcomeric myosin heavy chain
 MYH is highly expressed in the chewing
muscles of chimpanzees and is
responsible for the large size of these
muscles in this and other non-human
hominins
 in humans, MYH has been inactivated by
a frameshift mutation that occured about
2,4 Myr
OR
 = olfactory receptor genes
 these are approximately 1200 functional
OR genes in the mouse genome, but only
550 in humans
 = apparently selective pressures to
maintain OR gene functionally are relaxed
in humans
Olfactory Receptor Genes
 the remote ancestor of mammals carried a single
gene for detecting odors that has been
duplicated many times
 as a result, humans today have about 1 000 olfactory
receptor genes
 mice have 1 300
 more recently , about 60% of human olfactory
receptor genes have been inactivated by
mutations
 whereas mice have lost only 20% of theirs
 …this dramatic difference demonstrates that a
versatile sense of smell is more important to
mice than it is to us!