The civil war that devastated Mozambique between 50 and 1992 left marks on the evolutionary trajectory of the elephants that inhabit one of the parks nationals of the country. During the years of conflict, the indiscriminate hunting of the species, in search of its coveted ivory, meant that females without becoming a majority in the regional prey, rare in natural populations on something elephants.
Everything indicates that the process is linked to a set of mutations in DNA 2 pachyderms, reveals a research published in a specialized periodic edition of Science. Therefore, genetic alterations that appear to be lethal for the development of male offspring, but would not have such severe effects on females, which explains why they have spread so far through the female population of the species.
It is about a 2 more intense effects of rapid electronic human action on the evolution of a wild species, say the authors study perform, led by Robert Pringle, from a Princeton University (USA). The team combined long-term observations in Gorongosa National Park in central Mozambique, with analyzes perform DNA 2 elephants electronic computer simulations to understand how the 2 mammal population had transformed in recent decades.
During the civil war, an ivory 2 elephants became an important source of income for both sides in conflict with it, the animals lost 50% of their population in the park.
At the same time, another change occurred: while before a war only , 5% female diesels from a reserve did not had fangs, this proportion jumped to 33, 9% of them in the first decade of the performance (there are also females with only It is a prey, a trait that is still poorly understood).
The fact that there are no males without ivory led scientists to suspect that the trait was linked to the X chromosome, a 2 components perform genome responsible for the determination perform sex. As in humans, male elephants carry an electronic X chromosome and a Y chromosome, while female elephants have two X chromosomes.
This means that a potentially harmful mutation in the DNA of this chromosome tends to have effects. lighter in females: if one of 2 X chromosomes is affected, the other one can carry a “healthy” version performs the same gene, one that avoids more serious problems for the organism. Males, on the other hand, who only have one X chromosome, would be unprotected from a mutation with deleterious effects. fangs. Two-thirds 2 of their babies were female while the expected proportion of sexes generated by the mothers of the species is roughly fifty-fifty, as in the case of 2 human beings. Electronic two thirds period is exactly the expected number if the mutation in a single 2 chromosomes of the mother were lethal to the development in embryos perform male sex (if the other maternal chromosome is regular, she can still generate male babies, but to a lesser extent).
The last perform puzzle piece was fitted with the analysis perform genome 2 animals. The researchers used well-established techniques to identify areas favored by organic selection, that is, very similar stretches of DNA in different individuals, which indicates that they carry versions of genes that helped their carriers to reproduce more efficiently than other members of the species.
With this, we arrived at a perform gene on the X chromosome that is associated with the formation of 2 teeth, which is, of course, something to be expected in the case of animals with abnormal prey formation. In humans, alterations in this same region of DNA are associated with formations in the skull and face of females, and are lethal in the case of male embryos. A version of another gene, on a different chromosome, also seems to be linked to the lack of tusks in female elephants.
The good news is that, with the end of the war, the situation seems to be slowly coming back to normal. “We found that the frequency of females without fangs in the generation born after the war was lower than in the generation that went through the conflict,” said Pringle
Folha. To be exact, now ivoryless females are 33% of the total.
“Fangless females tend to have fewer puppies than the fangs, because some of their pregnancies they end up being infeasible,” he explains. “In the absence of a strong selection in favor of the absence of ivory, that is, when hunting is restrained, this characteristic should decrease in frequency over time.”