The Anaphylactoid Reaction in Wild Rats

Abstract

A recessive autosomal gene, probably identical with dx, previously identified in a stock of Wistar albino rats, was discovered in a stock of wild brown rats (Rattus norvegicus). This gene prevents the anaphylactoid reaction produced by the injection of dextran or fresh egg-white. Non-reactivity was outbred into non-albino stocks and was shown to segregate independently of the albino gene and not to be closely linked to other color genes, (for example, pink-eyed yellow and agouti). Wild black rats ( Rattus rattus) also carry this non-reactivity gene. The mutation from Dx to dx in the stock of Wistar albino rats where it was 1st discovered may have arisen a few years ago by chance crosses with non-reactor black or wild brown rats.