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1.
Trends Genet ; 38(5): 419-421, 2022 05.
Article in English | MEDLINE | ID: mdl-34776276

ABSTRACT

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.


Subject(s)
Chromosome Pairing , Meiosis , Chromosome Pairing/genetics , Chromosomes/genetics , Humans , Polyploidy
2.
Am J Bot ; : e16292, 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38439575

ABSTRACT

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. Subsequently, we also investigated how frequently polysomic inheritance has been reliably documented in autopolyploids. Pure or predominantly polysomic inheritance was documented in 39 of 43 putative autopolyploid species where inheritance data was available (91%) and in seven of eight synthetic autopolyploids, with several cases of more mixed inheritance within species. We found no clear cases of autopolyploids with disomic inheritance, which was likely a function of our search methodology. Interestingly, we found seven species with purely polysomic inheritance and another five species with partial or predominant polysomic inheritance that appear to be taxonomic allopolyploids. Our results suggest that observations of polysomic inheritance can lead to relabeling of taxonomically allopolyploid species as autopolyploid and highlight the need for further cytogenetic and genomic investigation into polyploid origins and inheritance types.

3.
Theor Appl Genet ; 134(6): 1711-1728, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33730183

ABSTRACT

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. However, this approach can be difficult, as it relies on factors such as ease of hybridization and genetic distance between the source and target, crossover frequencies and distributions in the hybrid, and ability to select for desirable introgressions while minimizing linkage drag. In this review, we outline the possible effects that climate change may have on crop production, introduce the Brassica crop species and their wild relatives, and provide an index of useful traits that are known to be present in each of these species that may be exploitable through interspecific hybridization-based approaches. Subsequently, we outline how introgression breeding works, what factors affect the success of this approach, and how this approach can be optimized so as to increase the chance of recovering the desired introgression lines. Our review provides a working guide to the use of wild relatives and related crop germplasm to improve biotic and abiotic resistances in Brassica crop species.


Subject(s)
Brassica/genetics , Climate Change , Hybridization, Genetic , Plant Breeding , Crops, Agricultural/genetics , Disease Resistance/genetics , Stress, Physiological
4.
J Pediatr Gastroenterol Nutr ; 61(5): 558-60, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26111293

ABSTRACT

To compare disability and emotional health in individuals with irritable bowel syndrome (IBS), fibromyalgia, or both, patients completed the Questionnaire on Pediatric Gastrointestinal Symptoms-Rome III, childhood Functional Disability Inventory (FDI), and the Behavior Assessment System for Children, Second Edition. Patients' (age range 8-18 years, 19 IBS, 12 fibromyalgia, and 12 both) FDI scores showed greater disability than scores from historically healthy patients. Fibromyalgia (FDI 22.5 ±â€Š12.7, P = 0.018) and patients with both (FDI 26.2 ±â€Š13.8, P = 0.001) averaged greater disability than those with IBS (FDI 10.6 ±â€Š7.9). Disability was correlated with anxiety and depression symptoms. Disability and psychological symptoms are important when evaluating individuals with fibromyalgia and IBS.


Subject(s)
Disabled Children , Fibromyalgia/complications , Irritable Bowel Syndrome/complications , Quality of Life , Adolescent , Anxiety/complications , Child , Depression/complications , Disability Evaluation , Disabled Children/psychology , Female , Humans , Male , Surveys and Questionnaires
6.
J Acquir Immune Defic Syndr ; 48(5): 599-606, 2008 Aug 15.
Article in English | MEDLINE | ID: mdl-18645511

ABSTRACT

BACKGROUND: In Ghana, programs to expand antiretroviral access are being implemented. In this context, the dynamic genetic evolution of HIV-1 requires continuous surveillance, particularly when diverse genetic forms co-circulate. METHODS: Phylogenetic and antiretroviral resistance analyses of HIV-1 partial pol sequences from plasma RNA samples from 207 Ghanaian individuals were performed. RESULTS: 66% of infections were CRF02_AG, whereas 25% were unique recombinant forms (URFs). All 52 URFs were characterized by bootscanning. CRF02_AG was parental strain in 87% of URFs, forming recombinants with genetic forms circulating in minor proportions: CRF06_cpx, sub-subtype A3, CRF09_cpx and subtypes G and D. Two triple recombinants (CRF02_AG/A3/CRF06_cpx and CRF02_AG/A3/CRF09_cpx) were identified. Antiretroviral resistance analyses revealed that six individuals, five of which were antiretroviral drug-experienced, harbored mutations conferring high level of resistance to reverse transcriptase inhibitors. No major resistance mutations were identified in the protease, although insertions of one and three amino acids were detected. CONCLUSIONS: The high frequency of URFs detected probably reflects a significant incidence of coinfections or superinfections with diverse viral strains, which increases the genetic complexity of the HIV-1 epidemic in West Africa. Monitoring of HIV-1 drug resistance might provide data on the implications of intersubtype recombination in response to antiretrovirals.


Subject(s)
Anti-HIV Agents/pharmacology , Drug Resistance, Viral/genetics , HIV Infections/epidemiology , HIV-1/genetics , Mutation , Recombination, Genetic , Genes, pol , Ghana/epidemiology , HIV Infections/virology , HIV Protease Inhibitors/pharmacology , HIV-1/classification , HIV-1/drug effects , HIV-1/isolation & purification , Humans , Molecular Epidemiology , Molecular Sequence Data , Phylogeny , Polymorphism, Genetic , Prevalence , Reverse Transcriptase Inhibitors/pharmacology
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