Plant & Animal Genome VI Conference

S17

TO PAIR, OR NOT TO PAIR

John Innes Centre, Colney, Norwich NR4 7UH, UK

Chromosome pairing in hexaploid wheat resembles with minor modifications the process occurring in yeast and Drosophila, but pairing in the Ph1 mutant wheat resembles that occurring in mammals and maize. Are mammals Ph1 mutants? Hexaploid wheat has the ability to efficiently assort its parental chromosomes during floral development so that virtually all the homologues are associated during pre-meiotic interphase. The major homology searching process in maize and mammals appears to occur only during meiotic prophase. If the alignment and association during pre-meiotic interphase is a result of searching genes and repeat sequences as against only genes in meiotic prophase, this would explain the apparent increase in pairing stringency found in hexaploid wheat. What is the likely mode action of Ph1? It affects centromere structure and has to stabilise repeats. The Ph1 locus might encode a protein analogous to CENP-B of mammals.

References

Review of Function

• To pair, or not to pair: Chromosome pairing and evolution, G. Moore, 1997 Current Opinion in Plant Biology, in press.

• Wheat, Aragon-Alcaide et al Current Biology, 1997 in press.
• Aragon-Alcaide et al 1997 Chromosoma 105 327.
• Yeast, Weiner, Kleckner 1994 Cell 77:977.
• Drisophila, Hiroka et al 1993 J Cell Biol 120:591.
• Mammals, Scherthan et al 1996 J Cell Biol 134: 1109.
• Towards cloning Ph1, Foote et al, 1997 Genetics in press
• Qu et al, 1997 Theor Appl Genet in press.