B (supernumerary) chromosomes are non-essential elements, non-beneficial and rather harmful
for the organisms that harbour them, but they are still frequently transmitted to the progeny at
greater than expected ratios based on Mendelian genetics. One of the B chromosome
accumulation mechanisms is the nondisjunction, when both chromatids remain attached to
each other and subsequently pass into the same daughter nucleus. This process is actively
controlled by the B chromosome itself, but information on molecular mechanisms of
nondisjunction is fragmented at best and no regulators have yet been confirmed and
characterized. Here we will use the maize B chromosome as a model to reveal molecular
machinery of nondisjunction during the second pollen mitosis. Transcriptome analysis focused
on pollen development along with the analysis of conservation of genes on the B chromosome
will provide list of candidate genes. To validate candidates, we will knock-out B-linked genes
using CRISPR/Cas9 technology.