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Cytoplasmic Factor (cytoplasmic + factor)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

CYTONUCLEAR INTERACTIONS CAN FAVOR THE EVOLUTION OF GENOMIC IMPRINTING

EVOLUTION, Issue 5 2009
Jason B. Wolf
Interactions between cytoplasmic (generally organelle) and nuclear genomes may be relatively common and could potentially have major fitness consequences. As in the case of within-genome epistasis, this cytonuclear epistasis can favor the evolutionary coadaptation of high-fitness combinations of nuclear and cytoplasmic alleles. Because cytoplasmic factors are generally uniparentally inherited, the cytoplasmic genome is inherited along with only one of the nuclear haplotypes, and therefore, coadaptation is expected to evolve through the interaction of these coinherited (usually maternally inherited) genomes. Here I show that, as a result of this coinheritance of the two genomes, cytonuclear epistasis can favor the evolution of genomic imprinting such that, when the cytoplasmic factor is maternally inherited, selection favors maternal expression of the nuclear locus and when the factor is paternally inherited selection favors paternal expression. Genomic imprinting evolves in this model because it leads to a pattern of gene expression in the nuclear haplotype that is coadapted with (i.e., adaptively coordinated with) gene expression in the coinherited cytoplasmic genome. [source]

Incipient speciation revealed in Anastrepha fraterculus (Diptera; Tephritidae) by studies on mating compatibility, sex pheromones, hybridization, and cytology

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009
CARLOS CÁCERES
It has long been proposed that the nominal species Anastrepha fraterculus is a species complex and earlier studies showed high levels of pre-zygotic isolation between two laboratory strains from Argentina and Peru. Further experiments were carried out on the same populations and on their reciprocal hybrids, including pre- and post-zygotic isolation studies, pheromone analysis, and mitotic and polytene chromosome analysis. A high level of pre-zygotic isolation had been maintained between the parental strains despite 3 years of laboratory rearing under identical conditions. The level of pre-zygotic isolation was reduced in matings with hybrids. There were also differences in other components of mating behaviour. There were quantitative and qualitative differences in the sex pheromone of the two strains with the hybrids producing a mixture. The pre-zygotic isolation barriers were complemented by high levels of post-zygotic inviability and sex ratio distortion, most likely not due to Wolbachia, although there was evidence of some cytoplasmic factor involved in sex ratio distortion. Analysis of polytene chromosomes revealed a high level of asynapsis in the hybrids, together with karyotypic differences between the parental strains. The combined results of the present study indicate that these two strains belong to different biological entities within the proposed A. fraterculus complex. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 152,165. [source]

CYTONUCLEAR INTERACTIONS CAN FAVOR THE EVOLUTION OF GENOMIC IMPRINTING

EVOLUTION, Issue 5 2009
Jason B. Wolf
Interactions between cytoplasmic (generally organelle) and nuclear genomes may be relatively common and could potentially have major fitness consequences. As in the case of within-genome epistasis, this cytonuclear epistasis can favor the evolutionary coadaptation of high-fitness combinations of nuclear and cytoplasmic alleles. Because cytoplasmic factors are generally uniparentally inherited, the cytoplasmic genome is inherited along with only one of the nuclear haplotypes, and therefore, coadaptation is expected to evolve through the interaction of these coinherited (usually maternally inherited) genomes. Here I show that, as a result of this coinheritance of the two genomes, cytonuclear epistasis can favor the evolution of genomic imprinting such that, when the cytoplasmic factor is maternally inherited, selection favors maternal expression of the nuclear locus and when the factor is paternally inherited selection favors paternal expression. Genomic imprinting evolves in this model because it leads to a pattern of gene expression in the nuclear haplotype that is coadapted with (i.e., adaptively coordinated with) gene expression in the coinherited cytoplasmic genome. [source]

Effect of genome composition and cytoplasm on petal colour in resynthesized amphidiploids and sesquidiploids derived from crosses between Brassica rapa and Brassica oleracea

PLANT BREEDING, Issue 4 2002
B. Zhang
Abstract The effect of genome composition and cytoplasm on petal colour was studied in Brassica. Three accessions of yellow-petalled B. rapa (2n= 20, AA) were crossed with a white-petalled B. oleracea var. alboglabra (2n= 18, CC) and with three cream-yellow-petalled B. oleracea var. gongylodes (2n= 18, CC) to produce resynthesized B. napus (2n= 38, AACC or CCAA) and sesquidiploids (2n= 29, AAC or CAA). Petal colour was measured with a Hunter automatic colour difference meter. The results revealed that petal colour in Brassica is controlled by nuclear genes and by cytoplasmic factors. Additive and epistatic gene effects were involved in the action of nuclear genes. When crosses were made between yellow-petalled B. rapa and white-petalled B. oleracea var. alboglabra, significant additive, epistatic and cytoplasmic effects were found. White petal colour was partially epistatic over yellow petal colour. When crosses were made between yellow-petalled B. rapa and cream-yellow-petalled B. oleracea var. gongylodes, only epistatic effects were detected. Yellow petal colour was epistatic over cream-yellow. [source]