In a γ-ray induced male sterile mutant of pea, the
ms gene inhibits meiotic initiation or arrests male meiosis either during pachytene, diplotene, prophase II or telophase II, or, permites its progression until microspore formation. The meiosis is abnormal involving PMCs, chromatin and/or nucleolar degeneration, nucleolar fragmentation or multiplication, sticky, clumped or clustered bivalency, chromatid breakages and irregular reunions, chromosomal stickness and unequal disjunction, abnormal monads to tetrad formations and complete microspore abortion. This mutant gene,
msg3, causing these anomalies is non-allelic to the other seven
ms genes isolated in pea. The
ms gene action in this mutant is unique being non-stage and non-site-specific, diffuse and staggered. Existence of a constellation of meiotic anomalies accompanying meiotic progression indicates broad action spectrum of
msg3 gene. The basis of evasion or endurance of about 50% PMCs and susceptibility of the remaining ones to the
ms gene post-translational products is not known. The influence of gene mediated enzyme(s) deficiency in limiting meiotic progression cannot be ruled out. Likewise, the impact of the environment over the versatility and prodigiousness of
ms gene action cannot be discounted. Can environmental influence be so selective or do buffering or inhibitory anther-specific genes exhibit variable or temporal and spatial gene action in the
msg3 mutant of pea is also not known. Mutations in the highly conserved region in the PB promoter gene the ‘anther box’ may have led to the arrayed male meiotic anomalies in this mutant.
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