Have our ape ancestors come further than us in terms of evolution?
In the six million years since the species split, Chimpanzees have come further in terms of evolution than their human cousins. That's the conclusion a group of scientists from the University of Michigan have come to. Jianzhi Zhang and his colleagues say that genes in chimps evolved in ways that were more beneficial than was the case with human genes.
Genes instruct our bodies to create proteins that are essential to functions like transporting oxygen to the cells. Changes to the DNA that effect the way these proteins are made are called functional changes while changes that don't are called silent changes.
“If we see an excess of functional changes (compared to silent changes) the inference is these functional changes occurred because they were positively selected, because they were useful in some way to the organism,” said study team member Margaret Bakewell, also of UM.
The study showed that far more genes in chimps evolved in beneficial ways than in their human counterparts. The reasons why might be as simple as the respective sizes of our communities.
Historically humans have had smaller populations that splintered into even smaller groups.Because of this, random events would play a larger role in humans evolution than natural selection.
Under the process of natural selection, gene variants that are beneficial get selected for and become more common in a population over time. But genetic drift, a random process in which chance “decides” which alleles survive, also occurs. In smaller populations, a fortuitous break for one or two alleles can have a disproportionately greater impact on the overall genes of that population compared with a larger one.
The researchers say chance events could also lead to more neutral or negative genes that could lead to disease. A fire or fierce winter storm might take as many of the strong as the weak and lessen the gene pool.
The concept is a fascinating one but, there's still only theories and not proof. How much don't we know about Chimps that might play a factor in the results? Let's see what the next million years brings to the table.