http://www.digitaljournal.com/tech-and-science/science/genetic-basis-of-why-carnivores-eat-meat-discovered/article/483040

Genetic basis of why carnivores eat meat discovered

Posted Jan 5, 2017 by Tim Sandle
Researchers have discovered the genetic basis of meat eating. This has come about after a review of the genomes of leopards, tigers, killer whales and Tasmanian devils. The research also raises questions about extinction.
Cecil the lion was a major tourist attraction at Cecil the lion was a major tourist attraction at Zi...
Cecil the lion was a major tourist attraction at Cecil the lion was a major tourist attraction at Zimbabwe's Hwange National Park before he was killed by an American dentist in July
, Zimbabwe National Parks/AFP/File
Meat-eaters tend to be at the top of the food chain and have strict meat-only diets. Such animals tend to be smaller in population, relative to other creatures, and have a low genetic diversity.
A science group have been studying the genetic make-up of carnivores and have produced data for 19 genomes relating to carnivores, herbivores, and omnivores, with the aim of reviewing the gene patterns. Matching the genomic information to known physical traits is of interest in order to learn more about the different groups of animals. Carnivores, for example, share physiological traits. These include shorter digestive tracts, certain amino acid requirements, and particular preferences in taste.
By focusing on certain species, like felines (namely leopard, cat, tiger, cheetah and lion) and non-felines (in this case: polar bear, killer whale and Tasmanian devil); and then comparing these carnivores with herbivores (the giant panda, cow, horse, rabbit and elephant were used) together with omnivores (here human, mouse, dog, pig and opossum were profiled), it was found that carnivores shared particular gene patterns and these patterns did not occur with either omnivores or herbivores.
The main differences were the presence of gene families with the carnivores which were enriched in the muscle myosin complex and actin cytoskeleton components. These areas of physiology are associated with muscles and movement. In addition, felines did not have as large a set of genes for digesting starch or sugars, or for the detoxification of plant material.
In discussion with Bioscience Technology, lead researcher Dr. Stephen O’Brien, who is the lead scientist at the Theodosius Dobzhansky Center for Genome Bioinformatics at St. Petersburg State University in Russia explains: “Diet is something that modifies genomes, so we asked, what can we find in these genomes — such as genes that have to do with sugar metabolism and energetics and processing food and taste receptors—that might explain this?”
The concern is that the primacy of some genes and the absence of others in the carnivores that sit atop of the food chain means they could find it harder to adapt as the planet and climate alter. This could put certain species at extinction risk. Cheetahs, for example, are facing the risk of extinction with just 7,000 animals left in the wild.
The findings are published in the journal Genome Biology, in a paper titled "Comparison of carnivore, omnivore, and herbivore mammalian genomes with a new leopard assembly.”