Ivory Harvesting Pressure on the Genome of the African Elephant: A Phenotypic Shift to Tusklessness

Abstract

The unique chequered pattern of elephant ivory has made it a desired commodity for the production of various works of art. The demand however outstrips the supply and with soaring prices, illegal tusk harvesting is thriving on the African continent. Formal restrictions placed on trade in elephant products have been ineffective in reversing the rapid decline in elephant numbers. We are presently facing the reality of extinction of free roaming elephant on the African continent. This paper describes the histogenesis of the chequered pattern, the genomic impact of ivory harvesting on the phenotype of breeding herds, and the contribution of science to tracing the origin of illegal ivory.

The African Elephant (<i>Loxodonta africana</i>): Mini-Review of an Endangered Species

“…The selection of these specimens will have consequences for the future generations, as has been proved in an investigation of elephants in southern Kenya [48]: both surviving individuals and those who born after the ivory harvest showed a decrease in tusk circumference at lip and tusk length, especially females, which can be justified by the greater tendency to seek large tusks in groups of elephants (usually related to females). This phenotypic change is based on genetic changes and the possibility of the disappearance of the ivory bearing gene can cause difficulties for the defence and feeding, but it can also represent hope for the future of the species [49]. The preference for older individuals, in addition to influencing the future phenotype of the species, could trigger problems in the social and hierarchical structure present in elephants.…”

“…The beauty of ivory enriches several artistic works, but it is the price associated with it that attracts more and more poachers, especially when the demand grows and the supply does not keep up with it [49]. The strong contribution to the conservation of L. africana comes from Southern African countries and this may not be enough to combat the demand for ivory from the far East Asia [34].…”

“…Science represents a strong ally in trafficking control, being very useful in tracing the origin of ivory [49]. Through multiplex PCR-electrophoresis assays, the origin of the ivory can be proven, ignoring the chances of it being false and allowing the potential traffickers to be penalized according to the severity of the conservation status of the species in question [63].…”

Elephant Genomes Elucidate Disease Defenses and Other Traits

“…While genomic approaches are useful for elephant conservation, the few elephant functional genomic studies currently available are limited to a small number of individuals and species [10][11][12][13] and the etiologies of many elephant traits with profound fitness (and therefore conservation-oriented) consequences have not yet been discovered. For instance, increased frequencies of tuskless elephants may be a response to selective pressures from ivory poaching [14][15][16] . The genes controlling tusk development, however, remain unknown.…”

Ivory as an Important Model Bio‐composite

“…In addition, or perhaps as a consequence of its different dimensions, the ivory of the forest elephant is generally denser than that of the savannah elephant (AESR ). Local conditions also affect ivory properties as best demonstrated by the brittle tusks of the savannah elephants that roam the Namibian deserts (Raubenheimer and Miniggio ).…”