Recently published research describes animals as well adapted to the conditions, including the behavior of other creatures like humans.
Such a human behavior, The Economist reported, can force radical changes on "species an evolutionary eyeblink."
Princeton University biologist Shane Campbell-Staton investigates how animals adjust to human creations such as pollution and cities.
As indicated in the report, his interest was piqued by a movie featuring tuskless female elephants of Gorongosa National Park located in Mozambique.
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Mozambique Civil War
The absence of tusks of these elephants was believed to be a result of another man-made creation, specifically the Mozambican civil war, as described in the Mass Atrocity Endings site, which started in 1977 and ended in 1992 and was partly paid for by elephant killing for their ivory.
Approximately 90 percent of pachyderms that lived in Gorongosa are believed to have been killed. According to biologists, they wondered if rising tusklessness might be an adjustment to make elephants less attractive to their human predators.
Dr. Campbell-Stato said it was a possible theory, although no one had actually tested it. Through a combination of surveys and old video footage, he, together with his colleagues, concluded that approximately 18 percent of the female elephants in Gorongosa were "tuskless" prior to the war.
Thirty years after, after it was over, the number had gone up to 50 percent. As suggested by computer simulations, the possibility of such a drastic change occurring by chance, even in a reduced population, was little.
Elephant X Chromosome
A NewsAroundWorld report said, aside from verifying the change, the researchers were able to unravel these animals' genetic roots. As the study specified, tusklessness is a result of a mutation in a gene on what the authors describe as the elephantine X chromosome, which is described in general by the National Library of Medicine. As with humans, two X chromosomes would make a female, and an X and Y would make a male.
Regrettably for males, researchers said, "mutation is a package deal" that comes with changes to genes nearby that delay the development of the embryo.
Males who are inheriting the mutant gene are dying before birth. Females, on the other hand, can avoid the deadly side effects if one of the two X chromosomes they have has a non-mutated gene, although they will still grow up tuskless.
Fortunately, for the females, the details of the manner the mutant gene is inherited are making it possible for them to inherit two copies.
Since mutant males are dying before birth, those surviving to reproductive age carry just the non-mutated versions of the X chromosome, guaranteeing their daughters will have at least a single copy, as well.
'Tusklessness' of Elephants
Currently, the continuous reintroduction of non-mutant X chromosomes from pales is setting a limit on the extent to which tusklessness can spread through the female populace.
Dr. Campbell-Staton explained that given time, as well as genetic recombination, evolution might unravel the "mutation for tusklessness from the maladaptive mutations" specifically in its nearby genes, opening the door for males to shed their tusks, as well.
He added, rumors have spread, of tuskless male elephants in the wild, although, so far at least, there's no concrete evidence.Finding one now seems unlikely. With the war over, the evolutionary pressure from poaching has eased. Tusks have gone back to being useful tools, helping their owners strip bark from trees and dig for water.
In recent years, the prevalence of tuskless females has dropped to roughly 33 percent. However, the speed of the change serves as a reminder that wars can change evolutionary history, as well as humans.
Related information about tuskless elephants in Mozambique is shown on News Headlines CN1's YouTube video below:
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