Synapsis and recombination in inversion heterozygotes.
Inversion heterozygotes are expected to suffer from reduced fertility and a high incidence of chromosomally unbalanced gametes due to recombination within the inverted region. Non-homologous synapsis of the inverted regions can prevent recombination there and diminish the deleterious effects of inversion heterozygosity. The choice between non-homologous and homologous synapsis depends on the size of inversion, its genetic content, its location in relation to the centromere and telomere, and genetic background. In addition, there is a class of inversions in which homologous synapsis is gradually replaced by non-homologous synapsis during meiotic progression. This process is called synaptic adjustment. The degree of synaptic adjustment depends critically on the presence and location of the COs (crossovers) within the inversion loop. Only bivalents without COs within the loop and those with COs in the middle of the inversion can be completely adjusted and became linear.
Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, Novosibirsk, 630090, Russia. torgasheva@bionet.nsc.ru
Anna A
AA
Torgasheva
Pavel M
PM
Borodin
D000818:Animals; D007446:Chromosome Inversion; D023902:Chromosome Pairing; D002877:Chromosomes, Human / Q000235:genetics* / Q000502:physiology; D033481:Chromosomes, Mammalian / Q000235:genetics* / Q000502:physiology; D003434:Crossing Over, Genetic; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D051379:Mice; D011995:Recombination, Genetic