Chromosome pairing in altered constitutions and models of synapsis and crossing-over

Abstract

Metaphase trivalent frequencies from a number of new chromosomal constitutions (various combinations of maize chromosome 2-Tripsacumhomeologue primary and secondary interchanges) are presented and compared to previous findings from similar material. It is suggested than an underlying direct relationship may exist between extent of gentic map present in duplicate and triplicate and expectation from a sharing of map probability of crossing-over among all homologues. Theoretical considerations are discussed.