Apes Humans BFFs

Guardian Express Science News


UW Today reports that a model of the history of great apes during the past 15 million years has been fashioned through the study of genetic variation in a group of humans, chimpanzees, gorillas and orangutans.  The catalog of the genetic diversity of great apes is the most comprehensive yet compiled.  It illuminates the evolutionary histories of great apes from Africa and Indonesia. This resource will likely also aid in conservation efforts to preserve natural genetic diversity in animal populations.

The 79 apes selected for genetic analysis included those in the wild and those born in captivity.  They represent all six great ape species—chimpanzee, bonobo, Sumatran orangutan, Bornean orangutan, eastern gorilla, and western lowland gorilla—as well as seven subspecies.  Nine human genomes were included in the sampling.

The study was conducted by more than 75 scientists and wildlife conservationists from around the world.

Evan Eichler, at the University of Washington in Seattle, led the project.  The findings were published in the July 3rd edition of the journal Nature.

Analysis of the genetic diversity of the great apes will show how factors such as natural selection, variations in population growth, geographic isolation, migration patterns, and climatic and geological changes shaped primate evolution.  These elements factor into changes occurring along each of the ape lineages as they became separated from one another.

The evolutionary history of ancestral populations of great apes was far more complex than that of humans, even though early human species were present during the time of the apes’ development.  There were humans on the earth six million years ago or more.

The last few million years of chimpanzee evolutionary history show great fluctuations in population size, demonstrating great plasticity.  This follows the principle of “punctuated equilibrium,” in which periods of evolutionary idleness are interspersed with rapid changes in development.

But how are apes and humans BFFs?

In some ways, they’re not so friendly.  The origin of HIV, the virus which causes AIDs, was SIV, simian immunodeficiency virus, which killed thousands of chimpanzees, gorillas and other species of great apes.  SIV has been present in monkeys and apes for at least 32,000 years, and probably much longer. Viral strains from two of the primate species, sooty mangabeys (one species of Old World monkeys) and chimpanzees, crossed the species barrier into humans, resulting in HIV-1 and HIV-2.  The most likely route of transmission of HIV to humans involves contact with the blood of chimps, which were (and are) often hunted for bushmeat (meat from animals in West and Central Africa). Today “bushmeat” is also used to refer to the meat derived from the hunting of endangered ape species in many areas of the world.

 Studying primate evolutionary biology helps to gain insights into neuropsychiatric diseases such as autism, schizophrenia, and cognitive and behavioral disorders.

Ever since researchers sequenced the chimp genome in 2005, we’ve known that we share about 99% of our DNA with chimpanzees, making them our closest living relatives.

Apes and humans have strolled a long way together down the evolutionary path.  If one considers the classification of living creatures (kingdom, phylum, class, order, family, genus and species), apes and humans share six of the seven, even to the genus homo, composed of primate mammals.  This genus includes extinct human species as well as apes and humans.  The genus homo is estimated to be about 2.3 to 2.4 million years old.  It is only when we get down to the species level that Homo sapiens branches from the nineteen species of apes.

 We’re in the same phylum, chordata (animals with backbones), the same order (primates), and the same family (Homininae, which includes chimps, gorillas and orangutans).   Hominidae are defined as erect bipedal primate mammals. But there are theories that bipedalism truly began when the Homininae (sounds like Hominidae), the tribe that includes the human clan, disassociated itself from the Panini tribe, composed of chimpanzees.

Primates share a number of characteristic  They have hair instead of fur, finger nails instead of claws, opposable thumbs, binocular vision, prehensility (the ability to grasp with fingers and/or toes), padded digits with fingerprints (which means criminal primates can be caught by the FBI), and dependence on vision more than smell.  And, of course, primates have a higher brain to body size ratio than other mammals, bespeaking their higher level of intelligence.

Apes are sometimes referred to as “anthropoid apes.” A human being is basically a bipedal primate mammal.

All those congruencies and similarities make apes and humans BFFs.