Genetic variations enhance survival, performance within habitats

Lusk — During the Animal Grazing Behavior workshop Feb. 2 in Lusk, Dr. Fred Provenza of Utah State University discussed habitat selection and genetic adaptation in livestock and wildlife.
Provenza found that experiences early in life influence habitat selection. “Offspring go where they were taught to go by their mother,” he explained.
Studies conducted in the UK found that just as food preferences were learned, so were habitat preferences. Fostered offspring learned from the mother and followed her patterns for life, regardless of breed differences.
Provenza explained another case of learned habitat behavior that involved moose in Norway. Select moose were choosing not to migrate to the seashore with the majority of the species. There were no physical barriers and the question of why the select few didn’t migrate was asked.
Research lead to archeological evidence that the moose were historically hunted on their migration routes. As a result of that some changed their behavior and didn’t migrate. Today it is a tradition that has been passed on from generation to generation to stay at high elevations. The moose is no longer hunted in Norway, but some members of the population have locally adapted to staying at high elevations year-round, according to Provenza.
He describes this behavior as having a home field advantage in life. Knowing what and where to go and what poses danger or increases chances for survival is passed down through generations.
This is also known as predictive adapted response and can be summarized in three key points. The first says that early in life the responses are induced by the environment. Second is that responses can be changed neurologically, morphologically, physiologically and behaviorally. Last is the point that survival advantages are higher when the environment an animal lives in matches the environment it was reared in.
“That’s the kind of stuff that becomes really important because it’s changed animals at all levels. Billions of neurons in the central nervous system get hooked up in part due to learning and experiences. Experiences effect neurology and the patterns of connecting and firing,” said Provenza, adding that changing behavior also means changing neurons.
“Not only can one argue that the body determines the structure of experiences, but also that experiences are determining the structure of the body. Not only in the central nervous system but in the rest of the body as well,” explained Provenza.
Rumen shape and size was provided as an example. Rumens of goats raised on lower quality blackbrush are much larger than those of goats raised on higher quality forages. The size difference is due to the fact that a larger volume of lower quality forages is necessary to meet nutritional needs, so the stomach adapted as a means of managing the increased volume.
“Sheep in Argentina reared on poor quality grass hay have an enhanced ability to recycle nitrogen. On a poor quality grass diet that’s not very high in protein you need to be able to hold on to as much nitrogen as you can and they have the ability to do that,” added Provenza as another example.
Provenza said that according to Darwinian thinking the creation of new brain structures is a long, slow process that takes place only as a result of mutations that are then selected for. He feels the idea of plasticity creates another way of thinking.
“Genes are being flipped on and off. There’s a lot in that genome and depending on what happens genes are flipped on and off. This idea of plasticity creates another way that mutation and variation occur, introducing new brain structures and new structures in the whole body by non-Darwinian means. In a sense you don’t know what’s possible,” he said.
Provenza’s idea is based on the concept of Epigenetics. “You have an incredibly stable genome but that genome is activated as a result of the interplay of the organism and the environment. Sweeps of genes are being turned on and off as a result of that.”
As animals adapt to an environment their genomes adjust according. Knowledge of conditions in a specific location combined with genetic responses enable creatures to not only live but also excel where they are raised.
Heather Hamilton is editor of the Wyoming Livestock Roundup and can be reached at heather@wylr.net