Population Data for the Transferrin Variants in the Australian Merino

Abstract

SummaryPopulation data for the transferrin varil;mts in the South Australian and Camden Park strains of the Australian Merino are reported. In all, five variants designated A, B, C, D, and E were distinguished. The relationship between these variants and those reported in previous investigations of the Merino and other breeds has been determined. In two out of the six samples there were significant departures from Hardy-Weinberg expectations. It was observed that closed flocks with small effective population size, Camden Park and one South Australian (Roseworthy) flock had fewer than five variants, the number generally found in all strains of the Australian Merino so far examined. For the Roseworthy material it was possible to demonstrate that the parent population, Anama, had the five variants. Further, the two Roseworthy flocks derived from the Anama stock had significantly different gene frequencies from that flock.

Transferrin types and reproduction in sheep

“…Deviations from Hardy-Weinberg equilibrium may be due to a variety of causes (Smith, 1970) and data from specific matings may be more useful to evaluate selective forces. Cooper (1967) observed 5 BB : 7 BD : 12 DD lambs from matings of BD X BD, and we observed the opposite trend, with regard to DD homozygotes, of 4 BB : 7 BD : 2 DD ( Table 5). DD sheep have been rare at Babraham, and they have been deficient every year in all matings in which they have been expected, until 1973 when CD ram 18014 mated to CD ewes produced 1 CC : 8 CD : 6 DD lambs.…”

“…All seven of his homozygous lambs were CC. Cooper (1967) observed an excess of heterozygotes in offspring of two rams, one AC and one AD, which he suggested might be due to inbreeding, although he found that for another AD ram the inbred progeny were in a ratio of 30 heterozygotes to 44 homozygotes. Our data suggest a general advantage of heterozygotes when matings involve heterozygous sires.…”

“…Transferrin types have been reported to have an effect on reproductive performance in mammals, birds and fish (see Ashton & Dennis, 1971, for references). In sheep, significant deviations from expected numbers in the distribution of transferrin types in populations and in segregating matings have been reported (Cooper, 1967;Cooper et al, 1967;FCsiis, 1970FCsiis, , 1972FCsiis & Orbinyi, 1968;FCsiis & Rasmusen, 1971;Khattab et al, 1964;King & Fechter, 1967;Stormont et al, 1968). This paper presents data on frequencies of alleles for transferrins in Merino, Soay, Clun Forest and Finnish Landrace flocks as well as ratios of transferrin types of offspring in segregating matings.…”

Effects of crossbreeding and inbreeding on the frequencies of blood groups in three breeds of sheep

“…This was determined by starch gel electrophoresis in a discontinuous buffer system with Tris-citrate buffer at pH 7-6-7-7 and boric acid-sodium hydroxide electrolyte at pH 7-6-80. The notation of A, B, C, D, E is described by Cooper, Bailey and Mayo (1967). Transferrins now labelled G and M may have been present but undetected.…”

Two new sheep transferrin variants and the effect of neuraminidase

“…However, not all the described variants really exist. For a number of them it was found that they were artefacts which were caused by some form of deterioration of the serum samples (Ashton & Ferguson, 1962; see also Cooper, 1967, andStormont et al, 1968). Besides, several further variants were described which were detected in only a few serum samples and no evidence of their genetic control was published.…”