Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Heritability of IQ wikipedia , lookup
Public health genomics wikipedia , lookup
Population genetics wikipedia , lookup
Microevolution wikipedia , lookup
Human genetic variation wikipedia , lookup
Genetic engineering wikipedia , lookup
Genome (book) wikipedia , lookup
Medical genetics wikipedia , lookup
Genetic testing wikipedia , lookup
SIDESHOW FREAKS OF THE CERVID CIRCUS JAMES R HEFFELFINGER,~ Arizona Game and Fish Department, 555 N. Greasewood Road, Tucson, AZ 85745, USA Abstract: The public is inherently interested in freakish and bizarre things. As biologists we are often called upon to explain unusual conditions or abnormalities that are seen only rarely. Antler abnormalities are the source of many questions, but the causes of non-typical antlers can encompass a range of factors including genetics, injury, disease, parasites, hormonal imbalances, and more. Antlered does are reported every year somewhere in the U.S. Some of these are true antlered does or hermaphrodites, however, many are bucks with undescended testes. These cryptorchid bucks have all the male reproductive tissue in the body cavity and therefore can carry out a normal antler cycle, whereas antlered does do not loose their velvet. "Cactus" bucks with deformed and velvet antlers are usually caused by factors that interrupt the normal hormonal fluctuations or the ability of the antlers to respond to hormones. There are cases of injury to the skull producing a third antler and injury to leg bones resulting in antler deformations. Other abnormalities occasionally seen are the retention of spots along the back line of adult deer, "woolly" pelage, and longer mane hair in deer. Several variations of the normal coat color have been reported in various areas. Albino deer are the most striking of the color anomalies. Albinism is a recessive genetic condition, whereby animals lack melanin in their cells so all hair, hooves, and skin are without color pigments. These deer have white hair, pink eyes, pink noses, cream or pink hooves, and even white antler velvet. The pink color is caused by underlying blood vessels being visible through the non-pigmented tissue. Albinos also can't see well because of the lack of pigment in their eyes that helps block sunlight. Albino whitetail and mule deer have been reported in many states, but there are a few areas where this genetic trait is more common. Piebald, or L'pinto,"deer are partially or mostly white, but are not albinos. The piebald condition is also a genetic abnormality where only some of the cells can produce melanin. These deer usually have pigmented hooves, eyes, and skin, lacking pigment only in some areas of their pelt. Besides varying degrees of white fur, piebald deer may have other genetic abnormalities such as short legs, a bowed nose, arching spine, short jawbones, and oddly formed internal organs. Upper canine teeth are absent in deer except in rare cases. The upper canines grow out of the maxillary bones of the skull and are evolutionary "throw-backs" fiom a time when deer ancestors had well-pronounced fangs. When present, these canines are not large, but generally small peglike teeth just breaking the gum line. Many canines may be missed because they are too small to erupt fiom the gum tissue and are not visible by simply looking in the mouth. All these abnormalities will be illustrated with a discussion of the causes of each. WESTERNSTATESAND PROVINCES DEER AND ELK WORKSHOP 5-128 ' E-mail: [email protected]