Related Research Articles
The American Quarter Horse, or Quarter Horse, is an American breed of horse that excels at sprinting short distances. Its name is derived from its ability to outrun other horse breeds in races of a quarter mile or less; some have been clocked at speeds up to 44 mph (70.8 km/h). The development of the Quarter Horse traces to the 1600s.
Severe combined immunodeficiency (SCID), also known as Swiss-type agammaglobulinemia, is a rare genetic disorder characterized by the disturbed development of functional T cells and B cells caused by numerous genetic mutations that result in differing clinical presentations. SCID involves defective antibody response due to either direct involvement with B lymphocytes or through improper B lymphocyte activation due to non-functional T-helper cells. Consequently, both "arms" of the adaptive immune system are impaired due to a defect in one of several possible genes. SCID is the most severe form of primary immunodeficiencies, and there are now at least nine different known genes in which mutations lead to a form of SCID. It is also known as the bubble boy disease and bubble baby disease because its victims are extremely vulnerable to infectious diseases and some of them, such as David Vetter, have become famous for living in a sterile environment. SCID is the result of an immune system so highly compromised that it is considered almost absent.
The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western stock horse with a pinto spotting pattern of white and dark coat colors. Developed from a base of spotted horses with Quarter Horse and Thoroughbred bloodlines, the American Paint Horse Association (APHA) breed registry is now one of the largest in North America. The registry allows some non-spotted animals to be registered as "Solid Paint Bred" and considers the American Paint Horse to be a horse breed with distinct characteristics, not merely a color breed.
Lethal white syndrome (LWS), also called overo lethal white syndrome (OLWS), lethal white overo (LWO), and overo lethal white foal syndrome (OLWFS), is an autosomal genetic disorder most prevalent in the American Paint Horse. Affected foals are born after the full 11-month gestation and externally appear normal, though they have all-white or nearly all-white coats and blue eyes. However, internally, these foals have a nonfunctioning colon. Within a few hours, signs of colic appear; affected foals die within a few days. Because the death is often painful, such foals are often humanely euthanized once identified. The disease is particularly devastating because foals are born seemingly healthy after being carried to full term.
Autoimmune polyendocrine syndromes (APSs), also called polyglandular autoimmune syndromes (PGASs) or polyendocrine autoimmune syndromes (PASs), are a heterogeneous group of rare diseases characterized by autoimmune activity against more than one endocrine organ, although non-endocrine organs can be affected. There are three types of APS, and there are a number of other diseases which involve endocrine autoimmunity.
The Dales Pony is a British breed of pony or small horse. It originated in, and is named for, the Dales of Yorkshire in northern England. It is one the nine native mountain and moorland pony breeds of the United Kingdom, and belongs to the broader Celtic group of ponies which extends from Portugal and northern Spain to Scandinavia.
Glycogen-branching enzyme deficiency (GBED) is an inheritable glycogen storage disease affecting American Quarter Horses and American Paint Horses. It leads to abortion, stillbirths, or early death of affected animals. The human form of the disease is known as glycogen storage disease type IV.
Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not tobiano. Overo is a Spanish word, originally meaning "like an egg". The most common usage refers to frame overo, but splashed white and sabino are also considered "overo". A horse with both tobiano and overo patterns is called tovero.
Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Chestnut is characterized by the absolute absence of true black hairs. It is one of the most common horse coat colors, seen in almost every breed of horse.
Cerebellar abiotrophy (CA), also called cerebellar cortical abiotrophy (CCA), is a genetic neurological disease in animals, best known to affect certain breeds of horses, dogs and cats. It can also develop in humans. It develops when the neurons known as Purkinje cells, located in the cerebellum of the brain, begin to die off. These cells affect balance and coordination. They have a critical role to play in the brain. The Purkinje layer allows communication between the granular and molecular cortical layers in the cerebellum. Put simply, without Purkinje cells, an animal loses its sense of space and distance, making balance and coordination difficult. People with damage to the cerebellum can experience symptoms like unsteady gait, poor muscle control, and trouble speaking or swallowing.
A white horse is born predominantly white and stays white throughout its life. A white horse has mostly pink skin under its hair coat, and may have brown, blue, or hazel eyes. "True white" horses, especially those that carry one of the dominant white (W) genes, are rare. Most horses that are commonly referred to as "white" are actually "gray" horses whose hair coats are completely white. Gray horses may be born of any color and their hairs gradually turn white as time goes by and take on a white appearance. Nearly all gray horses have dark skin, except under any white markings present at birth. Skin color is the most common method for an observer to distinguish between mature white and gray horses.
Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and it is not uncommon to mistake dark chestnuts or bays for black.
Hereditary equine regional dermal asthenia (HERDA), also known as hyperelastosis cutis (HC), is an inherited autosomal recessive connective tissue disorder. It develops from a homozygous recessive mutation that weakens collagen fibers that allow the skin of the animal to stay connected to the rest of the animal. Affected horses have extremely fragile skin that tears easily and exhibits impaired healing. In horses with HC, the skin separates between the deep and superficial dermis. There is no cure. Most affected individuals receive an injury they cannot heal, and are euthanized. Managed breeding strategy is currently the only option for reducing the incidence of the disease.
Junctional epidermolysis bullosa (JEB) is an inherited disorder that is also known as red foot disease or hairless foal syndrome. JEB is the result of a genetic mutation that inhibits protein production that is essential for skin adhesion. Therefore, tissues, such as skin and mouth epithelia, are affected. Blisters form over the entire body causing pain and discomfort, and open sores leave newborn foals highly susceptible to secondary infection. The condition can be categorized into two types of mutations: JEB1 and JEB2. JEB1 is found in Belgian Draft horses, as well as other related Draft breeds. In contrast, JEB2 is found in American Saddlebred horses.
Lavender foal syndrome (LFS), also called coat color dilution lethal (CCDL), is an autosomal recessive genetic disease that affects newborn foals of certain Arabian horse bloodlines. Affected LFS foals have severe neurological abnormalities, cannot stand, and require euthanasia shortly after birth. The popular name originates due to a diluted color of the foal's coat, that in some cases appears to have a purple or lavender hue. However, not all foals possess the lavender coat colour, and colouring can range from silver to light chestnut to a pale pink. Carrier horses have no clinical signs and DNA testing can determine if a horse carries the gene.
The severe combined immunodeficiency (SCID) is a severe immunodeficiency genetic disorder that is characterized by the complete inability of the adaptive immune system to mount, coordinate, and sustain an appropriate immune response, usually due to absent or atypical T and B lymphocytes. In humans, SCID is colloquially known as "bubble boy" disease, as victims may require complete clinical isolation to prevent lethal infection from environmental microbes.
The popular sire effect occurs when an animal with desirable attributes is bred repeatedly. In dog breeding, a male dog that wins respected competitions becomes highly sought after, as breeders believe the sire possesses the genes necessary to produce champions. However, the popular sire effect is not just down to wanting to produce a champion. For example, in Staffordshire Bull Terriers there are several popular sires who are used by breeders to produce specific colours that are not favoured in the show ring. The popular sire is often bred extensively with many females. This can cause undetected, undesirable genetic traits in the stud to spread rapidly within the gene pool. It can also reduce genetic diversity by the exclusion of other males.
Hoof wall separation disease, (HWSD), is an autosomal recessive genetic hoof disease in horses. Research is being carried out at, among others, UC Davis School of Veterinary Medicine in Davis in California. The disease has been found in Connemara ponies and was earlier referred to as Hoof Wall Separation Syndrome, HWSS.
Ann Trommershausen Bowling was an American scientist who was one of the world's leading geneticists in the study of horses, conducting research in the areas of molecular genetics and cytogenetics. She was a major figure in the development of testing to determine animal parentage, first with blood typing in the 1980s and then DNA testing in the 1990s. She later became known for her studies of hereditary diseases in horses and equine coat color genetics, as well as research on horse evolution and the development of horse breeds. She studied the population genetics of feral horses, did considerable work to help preserve the Przewalski's horse, and was one of the founding members of the international project to map the horse genome. She was an adjunct professor at the University of California, Davis (UCD), and at the time of her death in 2000 was the executive associate director of the Veterinary Genetics Laboratory (VGL) there. Her unexpected death on December 8, 2000, at age 57 was attributed to a massive stroke.
Warmblood fragile foal syndrome (WFFS) is a genetic disorder seen in horses. At first it was studied in Warmblood horses, but it is also present in Thoroughbreds, and potentially in any breed with Thoroughbred ancestry or outcrossing such as Quarter Horses, Standardbreds, and Morgans. It is autosomal recessive, so both sire and dam must be carriers for a foal to be affected. Foals with WFFS are naturally aborted, stillborn, or euthanized. WFFS is a genetic defect of connective tissue and foals born with it have hyper-extendible, abnormally thin, fragile skin that rips easily.
References
- 1 2 3 4 5 6 Bailey, E (17 December 2011). "Screening for foal immunodeficiency syndrome". The Veterinary Record. 169 (25): 653–4. doi:10.1136/vr.d8118. PMID 22184351.
- 1 2 3 Scholes, SF; Holliman, A; May, PD; Holmes, MA (7 February 1998). "A syndrome of anaemia, immunodeficiency and peripheral ganglionopathy in Fell pony foals". The Veterinary Record. 142 (6): 128–34. doi:10.1136/vr.142.6.128. PMID 9507645.
- 1 2 Fox-Clipsham, Laura Y.; Carter, Stuart D.; Goodhead, Ian; Hall, Neil; Knottenbelt, Derek C.; May, Paul D. F.; Ollier, William E.; Swinburne, June E.; Brooks, Samantha A. (7 July 2011). "Identification of a mutation associated with fatal foal immunodeficiency syndrome in the Fell and Dales pony". PLoS Genetics. 7 (7): e1002133. doi: 10.1371/journal.pgen.1002133 . PMC 3131283 .
- 1 2 3 4 5 Carter, SD; Fox-Clipsham, LY; Christley, R; Swinburne, J (13 April 2013). "Foal immunodeficiency syndrome: carrier testing has markedly reduced disease incidence". The Veterinary Record. 172 (15): 398. doi:10.1136/vr.101451. PMID 23486505.
- ↑ "Foal immunodeficiency syndrome (FIS)". www.animalgenetics.us. Retrieved 2017-02-18.