ATAVISM: WHY SOME PEOPLE ARE BORN WITH TAILS.
ATAVISM: WHY SOME PEOPLE ARE BORN WITH TAILS Human beings aren’t known or born to have tails… but why are some people on rare occasions born with tails?.
Well two answers … it’s in the genes and evolution. First of all what is an atavism?
In biology, an atavism is a modification or change of a biological structure where an ancestral genetic trait reappears in an organism after having been lost through evolution in previous generations.
When genes for previously existing phenotypic features(physical characteristics) are preserved in DNA, and these become expressed through a mutation that either knocks out the overriding genes for the new traits or makes the old traits override the new one.
Evolutionarily traits that have disappeared phenotypically do not necessarily disappear from an organism’s DNA.
The gene sequence often remains, but is inactive. Such an unused gene may remain in the genome for many generations spanning millions of years even just dormant but intact.
But As long as the gene remains intact, a fault in the genetic control suppressing the gene can lead to it being expressed again.
In this case the gene responsible in the production of tail … it was a very expressive gene millions of years ago, but now it isn’t. But now it has lost its original function it use to have when we still needed it in assisting balance and mobility.
ATAVISM: WHY SOME PEOPLE ARE BORN WITH TAILS So how does this happen?
In order to understand this, it is important to note that all humans briefly possess tails while in the uterus(during embryonic development).
Specifically, certain fetal cells develop into a tail and then regress as a result of cell death, or apoptosis. Scientists have identified a gene called “Wnt-3a” as a principal regulator of this process of tail formation in mice.
If this is the case, then evolution can make a prediction that if you check the genome of a human we should be able to find this gene.
And unsurprisingly because of our knowledge of genetics and molecular biology, Scientists have also discovered that humans indeed have an intact “Wnt-3a” gene, as well as other genes that have been shown to be involved in tail formation (but have been suppressed for million of years).
Through gene regulation, we use these genes at different places and different times during development than those Animals that normally have tails at birth.
Should this process of gene regulation somehow go wrong , a person could indeed be born with a true tail , and a throw back happens as seen in the pictures below . .
This is not the only kind of example of atavism we have found in humans or even in other animals .. there are hundreds of other examples.
Science and evolution has a perfect answer. But One would then ask the question, for people who believe in creation, what is a gene that produces tail doing in the human genome?
Anyways like I always say , science is does not care about your favourite mythology it keeps marching on.
Credit to: Kel vin