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#wheat genetics

2 public questions tagged with this topic.

Plant Breeding 4

Ph1 gene in wheat ensures:

Pairing homoeologous1, Ph1 locus on long arm of chromosome 5B in hexaploid wheat Triticum aestivum encodes ZIP4-B2 protein that suppresses homoeologous chromosome pairing between related A, B, and D subgenomes, enforcing strictly homologous bivalent pairing during meiosis. Without Ph1, homoeologs from different subgenomes would synapse forming multivalents and translocations, causing sterility and aneuploidy, as seen in ph1 mutants where extensive homoeologous pairing occurs and multivalents observed cytologically. Ph1 promotes homolog recognition via telomere bouquet organization and restrict

Ref: Riley R & Chapman V 1958 Nature – Ph1 homologous pairing discovery; Griffiths et al. 2006 Nature cloning of Ph1

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Plant Breeding 4

Hexaploid wheat has chromosome number:

Common bread wheat Triticum aestivum is an allohexaploid that arose through two successive natural hybridizations followed by spontaneous chromosome doubling. First hybridization between einkorn relative Triticum urartu carrying AA genome 2n=14 and Aegilops speltoides related BB genome 2n=14 produced tetraploid wild emmer AABB 2n=28. Second hybridization of tetraploid emmer with diploid goat grass Aegilops tauschii DD genome 2n=14 and subsequent doubling yielded hexaploid ABD genome complement with basic chromosome number x=7. Therefore 6x = 42 chromosomes in somatic cells, 21 pairs, with 7 ch

Ref: Sears ER. Wheat cytogenetics; International Wheat Genome Sequencing Consortium 2018 Science 2n=42

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