DISPLACED AND TANDEM DUPLICATIONS IN THE LONG ARM OF CHROMOSOME 10 IN MAIZE

[摘要] Lc , an anthocyanin pigmenting factor mapping somewhat more than one unit distal to R , is borne on a chromosomal segment which is homologous with part of the R-r :standard duplicated segment. Deficiencies and tandem duplications of the R to Lc region arise from exchanges within these obliquely paired homologous segments. The deficiencies are transmitted with a high, although reduced, frequency by the male gametophyte and are homozygous viable. Yet, the R to Lc region is not duplicated either proximal to R or distal to Lc . Thus the Lc -marked segment and either the P - or the S -marked segment of R-r constitute a displaced duplication. Such an arrangement can initiate a tandem and displaced duplication cycle.——No evidence was obtained for fractionation of the compound phenotype conditioned by Lc .

[学科分类] 医学（综合）