Publications by authors named "Charles Addo Nyarko"

Article Synopsis
  • Successful interspecies hybridization requires a stable "2n" chromosome set to produce viable "n" gametes, often achieved by doubling chromosome numbers or through rare recombination events.
  • In a study of third-generation hybrids resulting from a cross between Brassica juncea and B. napus, chromosome numbers varied significantly, indicating a complex genome structure influenced by unreduced gametes.
  • The research found a higher frequency of unreduced gametes in the hybrids compared to the parent species, suggesting this mechanism is crucial for stabilizing and increasing fertility in hybrid offspring.
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Autopolyploidy is taxonomically defined as the presence of more than two copies of each genome within an organism or species, where the genomes present must all originate within the same species. Alternatively, "genetic" or "cytological" autopolyploidy is defined by polysomic inheritance: random pairing and segregation of the four (or more) homologous chromosomes present, with no preferential pairing partners. In this review, we provide an overview of methods used to categorize species as taxonomic and cytological autopolyploids, including both modern and obsolete cytological methods, marker-segregation-based and genomics methods.

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Polyploids must correctly segregate homologous chromosomes. We propose that this process is dictated not just by sequence similarity, but is also under strong genetic control that may vary between lineages. We also highlight how factors like partner availability and genome structure may influence sequence similarity needed for crossover formation.

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Climate change will have major impacts on crop production: not just increasing drought and heat stress, but also increasing insect and disease loads and the chance of extreme weather events and further adverse conditions. Often, wild relatives show increased tolerances to biotic and abiotic stresses, due to reduced stringency of selection for yield and yield-related traits under optimum conditions. One possible strategy to improve resilience in our modern-day crop cultivars is to utilize wild relative germplasm in breeding, and attempt to introgress genetic factors contributing to greater environmental tolerances from these wild relatives into elite crop types.

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