No abstract

Two new haemoglobin variants, provisionally named Hb G and Hb H, were found during a survey of 295 Welsh Mountain cross-bred sheep. Both haemoglobins appear to be beta chain variants controlled by genes allelic to those for the common forms Hb A and Hb B. Studies on an anaemic Hb AH and an Hb AG type sheep showed that Hb G, like Hb A, is replaced by Hb C in anaemia whereas Hb H, like Hb B, is not replaced.

SummaryFinnish Landrace sheep with low red cell GSH concentrations resulting from a defective transport system for certain arnino acids were crossed with Tasmanian Merino sheep with a red cell GSH deficiency due to impaired activity of the enzyme γ-glutamyl cysteine synthetase. Inheritance data showed that the two types of GSH deficiency were under independent genetic control. In the Finnish Landrace breed, the gene coding for the transport defect (Trn) was inherited as an autosomal recessive and sheep homozygous for this gene had high red cell concentrations of lysine and ornithine (Ly ×) as well as low levels of GSH. In the Tasmanian Merino breed the GSH deficiency behaved as if controlled by an autosomal dominant gene (GSHL). Backcross breeding experiments resulted in lambs which had inherited both types of GSH deficiency. Evidence suggested that such ‘double low’ GSH lambs had an impaired viability. In Tasmanian Merinos the GSH deficiency was established prior to birth. Newborn Finnish Landrace lambs were clearly separable into two types on the basis of their red cell lysine and ornithine content but not on their GSH concentrations.

Hybridomas were made by fusing mouse myeloma cells with spleen cells from mice immunized with bovine red cells. Sixteen cloned lines which secreted haemolytic monoclonal antibodies reacting with antigens in the A, B, F, Z and S blood group systems were established; one of the antibodies identified a new factor in the B system. Extensive tests on red cells from 1000 animals indicated that several of the antibodies are suitable for use in routine blood typing; others are of potential use for genetic studies of the bovine blood group systems.

Red cell GSH concentrations were measured in 83 pure-bred and 65 cross-bred Tasmanian Merino sheep. A bimodal distribution was found; 40% of sheep had mean GSH values of 27-3 + 1-2 mg and 60 % had 92-2 ±1-5 mg/100 ml red cells. Family data are limited, but they suggest that this difference is under genetic control, the gene for low GSH levels being dominant to that for high. Unlike GSH-low type Finnish Landrace sheep, GSH-low type Merino sheep do not have lower than normal red cell sodium and potassium concentrations.