Adaptation of gastrointestinal nematode parasites to host genotype: single locus simulation models

Table 3 Effect of the low WEC A allele in sheep depending on the mechanism by which sheep reduce WEC

Mechanism of the A allele	Sheep genotype	Mean adult worms^a			WEC mean^b		Effect of allele A(α%)	Mean pasture L₃^c
Mechanism of the A allele	Sheep genotype	Count	p	Age (days)	Count (epg)	p	Effect of allele A(α%)	Max nb (x10⁷)	p	Age (days)
E	aa	11 769	0.500	31.3	487	0.500
	Aa	8 776	0.516	31.2	352	0.516	22.4	4.72	0.489	15.2
	AA	6 610	0.531	31.2	268	0.531
M	aa	12 581	0.500	30.7	501	0.500
	Aa	8 916	0.518	27.3	356	0.518	29.7	4.93	0.488	15.2
	AA	5 067	0.534	25.6	203	0.534
F	aa	11 134	0.500	31.3	449	0.500
	Aa	11 344	0.500	31.3	354	0.508	21.9	4.22	0.488	15.2
	AA	11 267	0.500	31.3	252	0.516

Postulated mechanisms to reduce WEC in sheep through the ‘resistance’ A allele: E = reduced worm establishment, M = increased worm mortality and F = reduced female worm fecundity; epg = eggs per gram; ^anumber, age, and frequency of the alternate B allele (p) for adult worms; ^baverage effect on WEC (α) and p for deposited eggs; ^cnumber, frequency of p and age for infective L₃ larvae on pasture.

ISSN: 1297-9686