Metaphase I orientation of chain-forming interchange quadrivalents: A theoretical consideration

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The orientation behaviour of chain forming interchange quadrivalents at metaphase I was studied in three interchange heterozygotes of pearl millet [Pennisetum americanum (L.) Leeke] which involve chromosomes 1, 3, 6 and 7 in various combinations. Of these, two combinations predominantly produced rings and the third was a chain-forming type. The chain quadrivalents derived from the two ring-forming interchanges, as well as the chain quadrivalent generated by the third interchange, all showed one adjacent orientation at metaphase I (adjacent-1 or -2, depending upon the formation or failure of chiasmata and their positions in the different segments of the pachytene cross). Homologous centromere co-orientation leading to adjacent-1 and alternate-1 occurs following chiasma failure in the noncentric arms of the pachytene cross, and nonhomologous centromere co-orientation leading to adjacent-2 and alternate-2 occurs, following chiasma failure in the centric arms of the pachytene cross. Thus, it has been proposed that, unlike in ring quadrivalents, a specific chain quadrivalent will have only homologous or nonhomologous centromere co-orientations at metaphase I.

Original languageEnglish (US)
Pages (from-to)707-717
Number of pages11
Issue number3
StatePublished - Jan 1 1984

ASJC Scopus subject areas

  • Genetics


Dive into the research topics of 'Metaphase I orientation of chain-forming interchange quadrivalents: A theoretical consideration'. Together they form a unique fingerprint.

Cite this