Tuesday, June 5, 2007

Genetic Tests Reveal Asexual Reproduction in Animals

Scientists have confirmed that a shark kept in captivity did indeed produce an offspring in 2001 without the fertilization from a male. Officials at the zoo were hesitant to announce the discovery until they'd confirmed that the birth was through parthenogenesis, rather than through sexual reproduction.
This discovery is important to the conservation of sharks, and could prove a double-edged sword for the declining family of cartilaginous fishes. Parthenogenesis could potentially weaken genetic diversity and make sharks more susceptible to diseases. Should shark numbers continue to fall, this asexual reproduction could essentially keep them from further evolving to survive their conditions. However, some scientists believe this was very common in early animals whose survival depended upon being able to reproduce when numbers were not large enough, as when an animals gets separated from others in an isolated area.
Other animals to have recently surprised us with their ability to reproduce without sex are komodo dragons, with two confirmed cases last year at separate zoos.
This form of reproduction has recently been a suggestion as to what happened with honey bees mysteriously disappearing, as drones of a colony are clones of the queen, giving them less resistance to diseases.

for BBC article on sharks
for BBC article on Komodo dragons

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