Comment:
The alternative states of Amy 7B2, namely, Amy 7B2 and Amy 7B2m {1084}, are identical to the variation in band 2 {412}. The complete description of the a-Amy-B2 variation also includes variation in band 11 {412}.
Comment:
The presence of a-Amy1 reported in {1084} was confirmed by segregational tests in a CS/Jones Fife population and in a population derived from a tetraploid cross {1083}. The recombinations with a-AmyB1 were 9.3% and 22.3%, respectively. A further set of a-amylase genes, Xa-Amy-5 [a-Amy3], was identified in 5A, 5B and 5D by cross-hybridization with a-AMY-1 and a-AMY-2 probes {080}. Only one gene copy appears to be present at each locus. In rye, evidence was obtained for three a-Amy-1 genes, two or three a-Amy-2 genes and three a-Amy-3 genes {907}. Synthesis of a-amylase isozymes controlled by a-Amy-1 genes on chromosomes 6A and 6D is reduced in DT6BS compared to euploid CS. This result suggests the presence of a gene(s) on the long arm of chromosome 6B, which is (are) required for GA-induced alpha-amylase synthesis in the aleurone {0072}.
Comment:
Three other a-Amy loci, namely, Amy 6B2, Amy 6D2, and Amy 7B2, were reported {1084}. No variation was observed for the products of Amy 6D2 and Amy 7B2, although nullisomic analysis located the genes in 6DL and 7B, respectively. In accordance with the Guidelines, these genes are assumed to be part of the a-Amy-D1 and a-Amy-B2 loci, respectively. Amy 6B2 was observed to produce alternative phenotypes {1084}. In a test of the segregation of these phenotypes relative to two alternative products of Amy 6B1, the two loci were found to be linked with a recombination frequency of 20.6% {1084}. However, an attempt to confirm the presence of more than one a-Amy locus in 6BL was unsuccessful {007}.
Comment:
Two types of nomenclature were assigned to the genes encoding the a-AMY-1 isozymes. In one, allelic states were defined for individual isozymes {1084} whereas in the other, several isozymes were considered to be the products of compound loci {007,412}. This listing shows the 'alleles' described in {1084} which are assumed in {007} to be synonymous with the a-Amy-B1a through a-Amy-B1h nomenclature. Amy 4 and Amy 41 are unmapped alternatives {1084} which appear to be identical to zymogram bands [bands 9 and 9b {007}] forming part of the a-Amy-B1phenotype. Amy 6B1 [with forms Amy 6B1o, and Amy 6B14', considered to be mutually exclusive {1084}] and Amy 6B2 [with forms Amy 62 and Amy 6B2o {1084}] describe further aspects of a-Amy-B1 {007}. See a-Amy1 below for further consideration of Amy 6B2 {1084}.
Comment:
It was estimated {902} that there are two a-Amy-1 genes in 6A and five or six in both 6B and 6D, and three or four a-Amy-2 genes at each of the 7A, 7B, and 7D loci.
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