Species Survivals Genetic Diversity Critical Status

Posted on: May 20, 2015 3:29 pm



Species Survivals Genetic Diversity Critical Status

In a research published by Stanford scholars, scientists have found that it is not just numbers but genetic diversity that will help save the tigers from extinction.  Having lost 90 percent of their historical habitat almost half of the 3000 wild tigers in the world today live in India in national parks and reserves spread in fragmented habitats throughout the country.

“Numbers don’t tell the entire story,” said study co-author Elizabeth Hadly, the Paul S. and Billie Achilles Professor in Environmental Biology at Stanford and senior fellow at the Stanford Woods Institute for the Environment. The researchers say that as populations of tigers have begun to live in fragmented areas their genetic diversity too has reduced. If tigers from one area are allowed to mate with tigers in another area it will ensure genetic flow and the resultant offspring will have a better chance of survival.
They added that restricted areas lead to loss of genetic diversity which can in future also lead to lower reproduction rates, faster spread of disease and more cardiac defects, among other problems.

A New idea is to keep cross-breeding tigers of different wild populations and also captive tigers, which till now has not been done. “This is very much counter to the ideas that many managers and countries have now – that tigers in zoos are almost useless and that interbreeding tigers from multiple countries is akin to genetic pollution,” said Elizabeth Hadly a biology professor and senior associate vice provost for undergraduate education. “In this case, survival of the species matters more than does survival of the exclusive traits of individual populations.”

They also give the example of Florida Panthers, another predator. Since individuals from a closely related panther subspecies were introduced to the population, Florida panthers have seen a modest rise in numbers and fewer cases of genetic disorders and poor fitness.

This new research will shock all in love with the tiger and striving to save it from extinction. Comparing the DNA samples of ancient tiger skins with the DNA of present day tigers, scientists have found that the modern tigers have a very poor genetic diversity. For an endangered animal, this becomes yet another threat to its existence as poor genes only make the future generations more prone to diseases and weaker.

With limited mating partners, the genes that pass on from one generation to another begin to weaken. They are less resistant to disease pathogens, and more vulnerable to environment variability’s around them like temperature, weather changes, mass epidemic or natural disasters, surviving with and against competition etc.

Also, a faulty gene in one parent can easily pass on to the offspring and again with limited partners, the entire population in an area may carry that same faulty gene. In other words it means that if the animal cannot fight a disease such as malaria for example, each and every individual with the same gene is as weak. The entire population may wipe out in days during a malaria outbreak then.

Genetic Diversity ensures that new genetic combination keep occurring in the offspring’s to produce better, stronger individuals in the next generation.

“Not only have tigers lost a huge amount of genetic variation since the days of the Raj, they have also been partitioned. And because they cannot disperse around their habitat as they would normally, they are losing their genetic viability as a population even faster.” Almost 93 percent of their genetic variation is lost and now all tigers are actually carrying a very similar gene.

How in the US Captive Genetic Studies are the future.

The American Captive Exotic Feline Repository was founded in 2014 to create a centralized scientific resource for the captive exotic community. ACEFR is a multi-institutional distributed bank that receives and curates tissue and genetic samples in combination with health data for animals present in captivity within the United States, as well as information from subsequent scientific endeavors. This is a collaborative effort bringing together scientists from multiple academic institutions, conservationists, veterinarians, and animal husbandry specialists in an effort to direct scientific resources towards preserving these vulnerable species for future generations. Dr Brian Davis said “There Genome studies have shown that the American Population of Big Cats are significantly more genetically diverse and preserving species more diverse is better even in captivity.”

Captive conservation and management programs play an increasingly vital role in a world where habitat destruction and human encroachment continues to threaten many populations of endangered wild felids. International in-country species conservation efforts focus on preserving habitat and diversity in the wild in partnership with local communities.

Researcher, Dr. Brian W. Davis of Bethesda, who has worked with the genomics of exotic cats and other species for the purpose of conservation and discovery of disease mechanisms. Davis notes, “The long term survival and genetic health of vulnerable species is critical if we are to gain insights from these species about the biology underlying human disease and human disease pathology.” His colleague, Dr. Jan E. Janecka of Duquesne University, who has well recognized work in the field of conservation genetics for multiple exotic feline species, as well as disease genomics, states, “The key to long-term survival of a species is large effective population size and high genetic diversity.
In this case, survival of the species matters more than does survival of the exclusive traits of individual populations. A New idea is to keep cross-breeding tigers of different wild populations and also captive tigers, which till now has not been done.

Dade City’s Wild Things is proud to partner with Dr. Brian Davis and Dr. Jan Janecka, founders of the American Captive Exotic Feline Repository. Dade City’s Wild Things has provided tissue and genetic samples and data from many of there animals that reside here at the ZOO to help preserve these species in the future. For more information, including how other big cat facilities can participate, please visit acefr.org.