The earliest man on Earth dates back to 200,000 years, while the earliest gorilla is 100,000 years old. However, the chimpanzee could be the "Adam of it all" after scientists have found a paternal line that is 1 million years old.

Researchers from the University of Leicester, identified DNA sequences of a large part of the Y chromosome, passed from fathers to sons in a group of apes including gorillas, orangutans, bonobos and chimpanzees.

The findings, which was published online in the journal Genome Research, show that chimpanzees belong to an older lineage than other ape species, including humans.

How Do Scientists Determine Ages Of "Adams"?

The study specifically considered mitochondrial DNA in these animals. This helped scientists make a genealogical or chromosomal trees to be used to compare between species.

The first-in-line ancestor of a this genetic family tree is otherwise known as a "Y-chromosomal Adam". In this case, scientists can be able to determine the ages of "Adams" by comparing species in the tree.

"It's interesting to compare the shapes of the trees between humans and our great-ape relatives. Considering both Y chromosome and mitochondrial DNA trees, humans look much more like gorillas than chimps," Professor Mark Jobling from the University of Leicester's Department of Genetics said.

The Study's Implications

The study sheds light on the way humans have mated for the last 200,000 years. The findings show that female humans and gorillas were pickier in choosing their partners than chimpanzees and bonobos.

The Y chromosome tree for gorillas is very shallow, which means that few males have offspring within groups, while what can be said of the chimpanzee's is that it's quite nonselective. This means that chimpanzees mate with each other more broadly.

The study also shows that for thousands of years, it's the nature of humans to choose mates or partners. It is likely that male humans practice a polygynous system of mating, wherein one male can have a relationship with two or more females, which gorillas also practice.

Chimpanzees, on the other hand, practice a multimale-multifemale mating system or what they call a "free-for-all" practice.

Photo: Aaron Logan | Flickr