Dataset features


Application: Gene expression microarray analysis
Number of samples: 10
Release date: Mar 31 2009
Last update date: Mar 20 2012
Access: Public
Taxon: Haemonchus contortus, Bos taurus, Ovis aries
Dataset link Differential gene expression of hair and wool sheep infected with Haemonchus contortus

Experimental Protocol

This experiment utilized 24 hair and 24 wool lambs. Wool lambs were from a composite line of 50% Dorset, 25% Rambouillet, and 25% Finnsheep breeding established in 1983. Hair lambs were derived from St. Croix and Barbados Blackbelly ancestors and were at least 87.5% St. Croix. Lambs were born in January, raised under field conditions with no effort to prevent parasite infection, and were 4 to 5 months of age at the start of the study. Equal numbers of female and castrated male lambs were represented, and body weights ranged from 14 to 35 kg. Levels of parasitemia were not quantified before the start of the study, but signs of clinical haemonchosis had not been observed for any of the experimental animals. However, to further standardize prior exposure levels, all lambs were drenched weekly with 3,000 infective third-stage larvae (L3) of H. contortus for 4 consecutive weeks before initiation of the study. The experiment was thus designed to compare breed differences in acquired immunity. Six infected animals of each breed were sacrificed at both 3 and 27 days after infection. These days were selected to represent the response to larvae (day 3) and adult worms (day 27). Control animals were sacrificed at day 17, 27, and 38, relative to day 0 of infected animals. The cDNA from one wool and one hair lamb were hybridized on each slide. Pairings were made randomly within the same infection status and collection day, resulting in 24 microarrays per tissue. Direct comparisons were thus made on each array for hair versus wool sheep within each infection status group and day of sampling, and the experimental unit for the study was a hair and wool lamb pair with the same infection status and day of sacrifice. To minimize effects of dye bias, an equal number of hair and wool sheep samples were labeled with Cy3 and Cy5 dye. Thus for each collection time, breed, and infection status, random assignment of Cy3-dye labeling for hair lambs and Cy5-dye labeling for wool lambs was made for one half of the samples. The remaining hair sheep samples were labeled with Cy5 dye and remaining wool sheep samples were labeled with Cy3 dye.








Kathryn MacKinnon
David Notter