Table 4.

Relationship between the breeding types and MDR1 genotype in Shetland Sheepdogs

MDR1 genotypea	Pedigree Shelties
	Outbreeding	Inbreeding	Linebreeding
MDR1 (−/−)	0	0	0
MDR1 (+/−)	2	1	2
MDR1 (+/+)	29	0	12

Note:

^aNumber of animals found in each situation.

Abbreviations: MDR1 (−/−), genotype with two mutant alleles, homozygous for the deletion; MDR1 (+/−), genotype with one wild type and one mutant allele, heterozygous for the deletion; MDR1 (+/+), genotype with two wild type alleles, homozygous.