Clinical Genetics

Question 0

Describe the cat blood type system

Answer 0

One gene, 2 alleles: A or B.
A is dominant over B.
Can have AB, more dominant than B, less dominant than A.
Type B cats all have natural antibodies to A antigen.
1/3rd Type A cats have weak antibodies to B.

Question 1

Describe how a male cat can be tortoiseshell in colour.

Answer 1

XX’Y - Klinefelters Syndrome. Some cells will activate the X’ (and be ginger) whilst some will activate X and will be coloured based on autosomal coat genes.
Chimeric cat - X’X/XY mixture of cell lines, two zygotes fuse. Some cells have X’X and some have XY. Therefore some patches of ginger.

Question 2

Describe the dog blood typing system

Answer 2

13 blood groups, 5 antiserum tests. DEA1,3,4,5,7,8. DEA1 has 4 alleles (including null), rest have 2 (including null).

Question 3

Describe the blood typing system in a horse.

Answer 3

13 groups. A,C,D,K,P,Q and U.
C,K,U = one antigenic product with two alleles (including null)
A,D,P,Q = produces two or more antigens, controlled by multiple alleles.
A^a is gene loci A, antigen a. Horses do not have antibodies to foreign blood unless sensitised.

Question 4

Give an example of a selection scheme in Dogs, performed by the kennel club.

Answer 4

1. Eye screening
2. Hip dysplasia scheme
3. Elbow dysplasia scheme
4. Syringomyelia