Inheritance of an abnormal haemoglobin haplotype in horses and its possible influence on blood values.

The study explores the inheritance pattern of an unusual hemoglobin (Hb) haplotype (genetic variation) in horses, specifically from a native Norwegian Trotter breed, and its potential impact on blood values. The researchers examined offspring from a stallion carrying this abnormal Hb to study its transmission and effect.

Experiment Setup

• The researchers carried out a breeding experiment involving a Norwegian Trotter stallion with an abnormal Hb haplotype labeled as N and with Hb type BI/N. This stallion fathered six offspring in the experiment.

Abnormal Haplotype Characteristics

• The abnormal N haplotype manages only one alpha chain (an important element of the molecule responsible for binding oxygen) which features the amino acids lysine at position 60 and phenylalanine at position 24. This composition is unusual compared to the normal hemoglobin structure of horses.

Haplotype Inheritance Among Offspring

• Three offspring inherited the N haplotype from the sire (father) and the BII haplotype from the dam (mother). The remaining three offspring received the BI haplotype from the sire.

Characteristics of Horses with BII/N Hb Type

• Horses having the Hb type BII/N demonstrate two Hb components when subjected to alkaline electrophoresis or isoelectric focusing, two methods used to analyze and separate proteins.
• The ratio between the fast (anodal) and the slow band (cathodal) is approximately 30:70. This suggests an atypical distribution of hemoglobin types in the blood of these horses.

Blood Value Comparison

• The study does not provide clear evidence of any significant differences in blood values between horses carrying the abnormal Hb type and normal horses of the same breed and age. Thus, the presence of the abnormal Hb may not have a prominent impact on the overall health or blood properties of the horse.