Zoology. Mozambique was born and grew up in the blood. Two years after its independence, in 1975, the former Portuguese colony was diven for fifteen years in a civil war that made 900,000 deaths and millions of displaced. This terrible conflict also made collateral victims: elephants. The two camps used from the ivory trade to finance their purchases of arms. This quasi-official poaching has reduced the population of Pachyderms by more than 90%, so that only a few hundred people stays in a country where they counted in thousands.
And again, some of them have lost their defenses. Not that they have been decided by the poachers. But by their massive slaughter, the ivory hunters selected a genetic anomaly that deprives some females of defenses. The phenomenon had already been described in Mozambique but also in other countries such as Kenya, Tanzania or South Africa, where the giant hunting of the savannah has heavily seven. For the first time, an international team quantifies precisely. In The science journal of October 21 , it also describes the genetic mechanism at work and identifies the two genes responsible for this “artificial selection”.
Scientists have gathered all they have been able to find studies, censuses but also videos or photos of the elephant populations of Gorongosa National Park, before, during and after the Civil War. The table they offer is edifying: the anomaly, which affected 18% of the females in the early 1970s, struck 52% at the exit of the conflict and still 30% in the first generation of young elephants born after the war. They then tried to simulate different transmission scenarios of this character. Robert Pringle, professor of evolutive biology at the University of Princeton and coordinator of the study, takes the maximum precautions to deliver the result: “poaching has existed for centuries. But it has been particularly intense during the civil war. And We show that it is extremely unlikely that such a change has appeared without a very strong selection of the phenotype. “In other words, without poaching, such a phenomenon would be impossible (a word approximately banned from the scientific vocabulary).
Modification of two genes
The data collected, both on the male-female ratio and on the mother-to-daughter transmission, have identified another scenario: that of a dominant mutation but placed on the X and fatal chromosome to young males. Indeed, if the anomaly, observed here and there and longtime, remained mysterious, a finding was necessary: it affected only the females. The reason is that affected male embryos can not grow at its end. “In normal times, the mutation can not impose itself since the affected females see their reproductive success singularly diminished”, insists Robert Pringle. On the other hand, in the conditions of extreme poaching, where, according to the science article, the chance of survival of mutant females in the twenty-eight years observed is five times greater than that of their armed congeners, it is impose.
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