Study of juxtaposition effect in maize using three-gene chains

The recombination frequency in maize in marker chains ws3-lg2-gl2 (chromosome 2) and c1-sh1-wx1 (chromosome 9) was studied. In mosaic maize genotypes, in chromosomes of which homozygous and heterozygous regions alternate, the stimulating effect of external homozygous background on recombination frequency (the juxtaposition effect) depends on marked heterozygous interval length and increases as it decreases. The presence of homozygous fragments within the marked interval can lead to disappearance or weakening of the juxtaposition effect, as well as to redistribution of crossovers within the interval. In maize, unlike Arabidopsis, the juxtaposition effect is not accompanied by disappearance or decrease of interference.