Appendix - A horse with an unusual haemoglobin phenotype

Abstract

In addition to the studies on Norwegian horses described by Clegg in the main paper, we have been carrying out surveys in various parts of the world in an attempt to identify unusual horse haemoglobin phenotypes. Out of approximately 500 samples, we have found one horse in Iran whose Hb pattern on starch gel electro­phoresis is completely different from any other horse studied. It had a fast/slow Hb ratio of 33/67, the fast Hb having Phe only at α f 24 and the slow Hb having Tyr and Phe in the proportions 2Tyr/1 Phe at α s 24. No other differences between the α f - and α s -chains were found apart from the expected lysine/glutamine substitution at α 60. A search through the literature revealed one other reported instance of a horse having more slow than fast Hb (Osterhoff 1966), but no quantitative data were given. A possible explanation is that this horse is a heterozygote for the | 60 α 24Phe f 40 α 24Phe s gene-pair, i. e. BII (main paper), and a new gene-pair | α 24Tyr s α 24Tyr s (or perhaps α 24Tyr s alone).