NEXT

CENOZOIC ERA

PALEOGENE PERIOD

Eocene Epoch

55-34 million years ago

HOME
PREVIOUS
prosimian

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.

GENETIC CHANGES
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 selection.