Deer genetics: Mother Nature can’t be outwitted (Part 4)
Heritability lends an important aspect that sides with the mindset that we can’t alter antler genetics in wild deer populations through culling. For offspring to receive and exhibit a trait from their parents, the trait must be heritable. This means that the variations of a specific and observable trait can be attributed to genetic components rather than environmental ones.
Genotype refers to the genetic makeup of an inheritable trait, like height or eye color, an offspring receives from its parents. A genotype may or may not be an expression of what you can physically observe. Phenotype, on the other hand, describes an observable, physical expression of the genotype. A phenotype can reflect a conflict between nature and nurture.
The scientific “mumbo jumbo” here can get tremendously confusing, but the gist is quite simple. Is the trait a function of the way the offspring was born, or is the trait a function of external circumstances and/or what was learned?
In free-ranging deer populations, it’s impossible to determine heritability, for the simple fact that we have no available genetic background on deer, and our real-life observations are minimal at best. Therefore, we have no way to know what we’re removing, or the implications our actions may have if we were to cull a specific buck because of an unsubstantiated guess.
In a study conducted by Harry A. Jacobson, Professor Emeritus, Mississippi State University, studied the genetic relationship to antler development.
“Captive deer demonstrate that heritability of antler traits for yearling bucks are low, and that more important than heritability, was the significant influence of the dam. The results of these studies argue against the practice of culling spikes for the purpose of genetically improving antler traits.”
In a separate study by Jacobson that took place from September 1997 through January 2000, 15 fawn and yearling bucks were captured, tagged and released on a 2,300-acre high-fence property. Fourteen of the bucks survived to at least 3-years-old and 12 survived to 4 or older. The bucks were photographed each year to document antler growth. As yearlings, seven of the bucks were spikes, and six of them had forked antlers. One buck wasn’t photographed until he was 2-years-old.
Jacobson concluded that, “while some spikes had smaller antlers than forked antlered yearlings, through three years of age, by four years, there were no apparent differences and the buck ending up with the most impressive antlers was a spike as a yearling. These results demonstrate the importance, and need for caution, in making management decisions.”
Read more about this in the Aug. 11 issue of Illinois Outdoor News.