An evolutionary process is causing some African elephants to have no tusks.
The brains of elephants are able to develop in a process known as ‘opthalmogenesis’, where genes are duplicated and the ends of the gene become interdependent, according to researchers.
The result is an increase in the number of genes that cause muscle and tendons to be replaced with bone. The elephants with no tusks also have more bones available to house the rest of their body.
A southern Malawian elephant (pictured) now has no tusks due to an ‘opthalmogenesis’ in which genes are replicated
The researchers carried out tests on tissue of a southern Malawian elephant with no tusks, known as Shenje.
They found Shenje’s genetic material had been duplicated because of a process known as ‘opthalmogenesis’.
Opthalmogenesis is an evolution process where an increase in gene numbers increases the size of the number of specialised cells, in this case muscle and tendons which become replaced with bone.
To test whether this could be the cause of elephants being affected by poaching the researchers found a trace of an opthalmogenesis in a San elephant’s stem cells.
The researchers also believe the dimpling of their feet could be an other factor involved.
This is a phenomenon where a central part of the toe stays straight whilst other parts are bent and detached.
The dimpling of the feet could be related to an increase in muscle in the forelimbs, which increases the ankle bone rather than the foot, and therefore the likelihood of cats attacks.
Dr Matthew Ritter of the University of Liverpool said: ‘The San Elephant is unique among African elephants, with many of its characteristics acquired with the ancestors of modern elephants through human intervention, such as loss of memory, and the loss of their physical uniqueness.
‘That’s why we wanted to investigate why in spite of their invincibility in the wild, the elephants were so vulnerable to humans.
‘Analysis of DNA in elephants from different species of San Elephant species with no tusks, such as Shenje and the San elephant from Malawi, provided an explanation, with exposed muscles allowing bones to flex downwards even at high speed, and less bone-enforced limb strength reducing their ability to jump over obstacles or chase a predator.
Shenje is one of four elephants who has no tusks, but two others have limited tusks for reasons unknown
‘We now know that elephants can ‘inhabit’ a smaller piece of bone which is removed to the total skeleton.
‘This process allowed some elephants to lose their tusks. These elephants lost their ability to hunt as their leg muscles have less force to propel them around.
‘However the ability to jump for themselves was not extinguished.’
The findings have been published in the journal Stem Cell Reports.