Mapping in the Maydeae : Tripsacum genes in Zea

Comparisons using cDNA (cloned DNA from expressed genes) from different species greatly increases our understanding and ability to identify the changes in the genetic content of related species through the process of evolution.This research utilized cDNA isolated from developmentally staged female flowers of Tripsacum, a relative of modem maize (corn) with differing modes of reproductive behaviors. The gene expression clone libraries potentially carry the gene(s) responsible for the regulation of fertility, both apomixis and sexual reproduction, in Tripsacum sp. A set of yeast genes with known functions in the reproductive cell division known as meiosis were also investigated, but failed to hybridized to DNA of the maize mapping population.The Tripsacum cDNAs, E2-42 and M2-62, showed monomorphic band patterns, i.e., no differences between individuals. Possibility the quantity of E242 and M2-62 Tripsacum cDNAs for these locus were highly conserved with respect to the fragment lengths generated by restriction digestion of the test individuals. The Tripsacum cDNA sequence L4-14 revealed polymorphic bands patterns when used as a probe for mapping. The L4-14 polymorphisms were scored as both 1:2:1 and 3:1 segregation ratios and mapped to a subset of ordered loci from the Maize Database genome bank, University of Missouri. Two genetic map regions were identified as linked to the L4-14 locus. These regions included bin 6.05-6.08 of chromosome 6 and bin 8.00-.05 of chromosome 8. Linkage to two different chromosomal regions indicated that the L4-14 sequence may be duplicated within the maize genome. Results and discussion of this investigation and analyses are presented.Department of BiologyThesis (M.S.