Equine Genetics Flashcards
What is the percent blood influence per generation in horses?
1st generation = 50%
2nd generation = 25%
3rd generation = 12.5%
4th generation = 6.25%
5th generation = 3.125%
What are the three types of pedigree crosses?
Cross breeding = crossing 2 different breeds
Outcross = crossing two of the same breed (Not related)
Line cross = crossing two specific families of horses
What is inbreeding?
Breeding horses that are related through the first or second generation
What is the difference between line breeding, and inbreeding?
Line breeding the horses are related in the third generation or further back
Inbreeding , the horses are related in the first or second generation
Name 3 genetic equine diseases/mustations
HYPP
GBED
HERDA
SCID
PSSM
MH
JEB
What is HYPP (hyperkinetic periodic paralysis)
A disease caused by a genetic mutation that disrupts the sodium ion channels resulting in excess potassium.
This causes muscle tremors, paralysis, and sometimes cardiac arrest
What is GBED in horses?
(Glycogen branching enzyme deficiency)
A fatal disease seen in quarter horses and paints. Leads to abortion or stillborn and foals who have it don’t live long.
Affected horses have a lack of enzymes needed to make sugars muscles need to function
What is HERDA in horses?
(Hereditary equine regional dermal asthenia)
A skin condition caused by hyperextensible skin (more elastic than normal skin)
Caused by collagen between skin layers not forming properly resulting in a horse that is easily injured
What is SCID in horses?
(Severe combined immunity deficiency)
Causes foals to be born with severely weekend immune systems (inherited as an autosomal recessive disorder)
Mostly effect horses of Arabian descent
What is PSSM in horses?
(Polysaccharide storage Myopathy)
A disease that causes abnormal accumulation of glycogen. This excess sugar can cause mild to severe muscle cramps, and muscle soreness/ weakness
What is MH in horses?
(Malignant Hyperthermia)
A genetic mutation that causes a life-threatening condition triggered by certain anesthesia, drugs, halothane or isoflurane
During an episode high amounts of calcium are released into the bloodstream causing muscle cramps, and extremely high fevers
What is JEB in horses?
(Junctional epidermolysis bullosa)
A fatal genetic disorder that causes fragile skin as a result of a mutation in the protein that anchors skin cells in the dermis.
Typically effects Belgium and American saddlebred horses
What are the 5 main coat colors for horses?
Bay, black, white, grey, chestnut or sorrel
