Ancestral primates evolved a number of features which
are shared among all modern primates.
THE ENDOCRINE SYSTEM
While there is only a single growth hormone gene in most vertebrates,
gene duplications have produced multiple copies in teleost fish, goats,
and primates (the latter of which have four genes).
THE CARDIOVASCULAR SYSTEM
Eta hemoglobin apparently was an embryonic hemoglobin in the ancestors
of eutherian mammals. In artiodactyls (deer, cows, giraffes, etc.) it
is still a functional gene. In primates, eta is a nonfunctional pseudogene.
In primates, eta hemoglobin becomes a pseudogene due to an A to G substitution
in the initiation codon and other mutations (stop codon at position at
position 429-31, and several deletions). In the primate lineage, the ?
globin was mutated and became a pseudogene.
THE REPRODUCTIVE SYSTEM
In female primates, the urinary and reproductive systems are separate
and labia minora develop around the vestibule.
The gene L-gluonolactone oxidase is required for an organism to synthesize
its own vitamin C. In primates and guinea pigs, this gene lost its function.
Presumably, the ancestral primates ate enough fruits that the inability
to synthesize vitamin C was no great disadvantage to them. Humans still
possess a non-functional pseudogene for this enzyme on chromosome 8p21.1.
CEACAM family of genes is expressed in epithelial and myeloid cells. There
are 8 genes in tandem near the family of pregancy derived glycoproteins,
to which they are related. There are 29 members (genes and pseudogenes)
of the carcinogenoembryonic (CEA) gene family in humans in a 1.5 Mb section
of chromosome 19.. Much of this expansion has occurred in primates after
separation from other placental orders.
The IFNa family seems to have arisen after the primate lineage arose.
In the electron transport chain, the gene COX8H underwent a more rapid