Genetic Variation in the Sheep Red Blood Cell

Abstract

Summary 1. There are 7 well‐established red‐cell antigen (blood group) loci. The R‐O system has 3 phenotypes, R, O and i, identified by the ‘naturally occurring’ antibodies, anti‐R and anti‐O. The R and O substances are also present in soluble form in some body secretions. The expression of R and O is controlled by a dominant gene I, epistatic in effect, at an independent locus from that of R. The systems, A, C, M‐L, B, D and X‐2 are identified by means of ‘immune‐type’ antibodies, and several of the loci have multiple alleles. An isoenzymic form of serum alkaline phosphatase is associated with the R‐O system. The frequency for the genes at the various loci has been determined in a limited number of breeds. 2. Some sheep red cells have high K+ and low Na+ concentrations (HK type, or Key), others have low K+ and high Na+ concentrations (LK type or Kea). Two other rare forms exist; Key type which is HK but with lower than normal K+ values, and Kep type which has approximately equal Na+ and K+ concentrations. The red cells of foetuses and newborn lambs have high K+ levels irrespective of their potassium genotype. HK cells have 3–4 times greater (Na+‐K+)‐activated ATPase activity, a 3–4 times increased rate of active K+ transport and a larger number of ouabain‐binding sites than LK cells. Antigen M is present on homozygous HK and heterozygous LK red cells, and antigen L is present on homozygous and heterozygous LK red cells. Sensitization of LK cells with anti‐L stimulates active K+ transport and ATPase activity and exposes a larger number of ouabain‐binding sites in these cells. Anti‐M has no effect. The red cells of newborn lambs only show weak L and M antigen activity. It is postulated that L antigen inhibits cation transport in LK cells by masking the pump sites on the membrane. Immature red cells in LK‐type sheep have a high rate of active K+ transport and yet have L antigen present. No satisfactory explanation for this has yet been advanced. There is no conclusive evidence that the potassium types have any significance from the point of view of adaptation or sheep breeding. The potassium‐gene frequencies are known for a large number of breeds. 3. Two allelic genes, Hb4 and HbB control 3 haemoglobin phenotypes, A, AB, and B. Foetal haemoglobin (HbF) is present in foetuses and newborn lambs. Sheep with HbA also synthesize small amounts of another haemoglobin (HbC) and under conditions of severe anaemia, synthesis of HbC takes over from that of HbA. No change in HbB is observed in anaemia. A rare haemoglobin (HbD) has been found in 3 Yugoslavian sheep. Hbs A, B, C and F differ in their physicochemical properties; they share the same alpha chains but their non‐alpha chains differ in a number of amino acids. HbD differs from HbA in one amino acid in the alpha chain. Certain genetic aspects are discussed. There is some evidence that sheep with HbA are less fertile than those with HbB. The gene frequencies for Hb are known for a large number of breeds. 4. Two isoenzymic forms of carbonic anhydrase are found in red‐cel...

A Dog Possessing High Glutathione (GSH) and K Concentrations with an Increased Na, K-ATPase Activity in its Erythrocytes

“…Such dimorphism of the cellular ion concentrations has been extensively used for studies of ion transport in cell membranes, although their clinical and physiological roles are not well understood [12,14,16]. Thus, the HK dogs are expected to provide new information to researchers in this field of study.…”

Genetic polymorphism of blood potassium in goat belonging to the different breeds and subbreed in Mongolia

“…This phenomenon is possible because the ATPase enzyme intimately involved in sodiumpotassium pump mechanism from the level of cell membrane [22]. The goats represent the second species after sheep, on the extent of potassium polymorphism investigation.…”

“…Many studies have noted distributional discontinuity of potassium in the blood of animals, which has suggested that this chemical element presents polymorphism having genetic determinism [2,3,5,7,810,11,13,17,21,22]. The polymorphism of erythrocyte potassium was for first time detected in sheep by Evans and King [4].…”

Erythrocyte potassium, sodium and glutathione concentrations and their relationship with reproduction, body weight and fleece weight traits in Awassi sheep

“…Most animal cells maintain high internal potassium and low sodium ion concentration due to the activity of the sodium/ potassium-ATPase (Na/ K-ATPase) pump in the membrane, which uses energy derived from the hydrolysis of ATP to accumulate potassium ions and expel sodium ions. The enzyme ATPase is intimately involved in the potassium or sodium-pump mechanism (TUCKER, 1971). EVANS (1954) reported that erythrocyte potassium concentration varied in sheep and two distinct types could be found in British breed.…”