Search results for "ploidy"

Chimerism and genetic diversity within the cultivar group of pinots

2002

Three clones of Vitis vinifera cv. pinot gris were analysed at 50 microsatellite loci to assess the presence of intra-varietal genetic variability. Two clones revealed a polymorphism expressed by the presence of three alleles at 5 loci instead of the two expected for a diploid species. By sequencing the three alleles amplified at two loci, we confirm that they correspond to different allelic states of the same locus but differ in their number of repeat units. Such tri-allelic profiles could reveal periclinal chimeras in which the two cell layers of the apical meristem are genetically different. For two clones, this periclinal chimeric state has been deduced from the comparison of the genoty…

Morphological characteristics, microsatellite fingerprinting and determination of incompatibility genotypes of Sicilian sweet cherry cultivars

2007

Sicily has extensive germplasm of diploid sweet cherry (Prunus avium L.) that has not been well studied. In this investigation, 39 cherry accessions, selected from collections and farms, were analysed using molecular markers and characterised for various morphological and other agronomic characters such as flesh colour, fruit size, quality and, in some cases, ripening periods. Thirteen Simple Sequence Repeat (SSR) primer pairs, as well as two primer pairs for the incompatibility (S) locus, which amplified across the first intron of the S-RNase gene and across the intron of the SFB gene, were used in three multiplexed reactions to analyse the accessions. The number of alleles per SSR locus r…

Self-diploidization in Saccharomyces cerevisiae kar2 heterokaryons

1993

Zygotes isolated by micromanipulation from crosses of Saccharomyces cerevisiae strains, one of which carries a kar mutation, give rise most frequently to cytoductant colonies showing the nuclear constitution of either one of the two haploid parental strains. In crosses of kar2-1 strains to wild-type, about 10% of the cytoductants of both mating types are homozygous autodiploids. There is evidence indicating that self-diploidization occurs by fusion between sibling nuclei in the heterokaryotic zygote. Here we describe this phenomenon and propose to take advantage of it for the construction of genotypically-defined diploids able to mate, and of polyploid strains, which are useful tools in gen…

Human blastocysts derived from monopronuclear zygotes: a biological model for the study of ploidy, euploidy, topography and heteroparental inheritance

2019

No inbreeding depression but increased sexual investment in highly inbred ant colonies.

2012

Inbreeding can lead to the expression of deleterious recessive alleles and to a subsequent fitness reduction. In Hymenoptera, deleterious alleles are purged in haploid males moderating inbreeding costs. However, in these haplodiploid species, inbreeding can result in the production of sterile diploid males. We investigated the effects of inbreeding on the individual and colony level in field colonies of the highly inbred ant Hypoponera opacior. In this species, outbreeding winged sexuals and nest-mating wingless sexuals mate during two separate reproductive periods. We show that regular sib-matings lead to high levels of homozygosity and the occasional production of diploid males, which spo…

Pigmentary mosaicism in hypomelanosis of Ito

1998

We report on a female with mental and motor retardation, facial dysmorphism, abnormal pigmentation reminiscent to hypomelanosis of Ito (HI), and karyotypic mosaicism involving a small supernumerary marker chromosome. The marker chromosome was defined by fluorescence in situ hybridisation (FISH) as a ring X chromosome with breakpoints in the juxtacentromeric region. FISH analysis showed that the ring does not include the XIST locus at the X-inactivation centre and, therefore, may not be subject to X inactivation. X-inactivation studies with the HUMARA (human androgen receptor) and FMR1 assay showed a skewed X-inactivation pattern (85:15) with preferential inactivation of the paternal X chrom…

Intergenomic interactions affect female reproduction: evidence from introgression and inbreeding depression in a haplodiploid mite

2004

Nuclear and cytoplasmic genomes can coevolve antagonistically or harmoniously to affect fitness. One commonly used test for nuclear-cytoplasmic coadaptation relies on the breakup of coadapted gene complexes by introgression, potentially resulting in an increased frequency of nuclear alleles in deleterious interaction with an alien cytoplasm. We investigated the phenotypic effect of such genes on female reproduction in outbred and inbred introgressed lines of the haplodiploid mite Tetranychus urticae. Introgression changed female lifetime fecundity and increased male production, in ways suggesting a control of fecundity by nuclear genes. Conversely introgression reduced the fertilization rat…

Karyological and Molecular Characterization of Mullus surmuletus and Mullus barbatus(Pisces, Mullidae).

1992

The modal diploid number of 44 chromosomes has been found in Mullus surmuletus and Mullus barbatus (Pisces, Mullidae). Two middle-sized subtelocentric chromosomes are involved in nucleolus organization (NORs) in both Mullus species. Despite similarity in the NOR location, valuable differences in the restriction pattern of the ribosomal genes have been observed.

Spontaneous rate of clonal mutations inDaphnia galeata

2020

AbstractMutations are the ultimate source of heritable variation and therefore the fuel for evolution, but direct estimates exist only for few species. We estimated the spontaneous nucleotide mutation rate among clonal generations in the waterfleaDaphnia galeatawith a short term mutation accumulation approach. Individuals from eighteen mutation accumulation lines over five generations were deep genome sequenced to count de novo mutations that were not present in a pool of F1 individuals, representing the parental genotype. We identified 12 new nucleotide mutations in 90 clonal generational passages. This resulted in an estimated haploid mutation rate of 0.745 x 10-9(95% c.f. 0.39 x 10-9− 1.…

Similar Performance of Diploid and Haploid Males in an Ant Species without Inbreeding Avoidance

2013

AbstractUnder haplodiploidy, a characteristic trait of all Hymenoptera, femalesdevelop from fertilised eggs, and males from unfertilised ones. Males aretherefore typically haploid. Yet, inbreeding can lead to the production ofdiploid males that often fail in development, are sterile or are of lowerfertility. In most Hymenoptera, inbreeding is avoided by dispersal flightsof one or both sexes, leading to low diploid male loads. We investigatedcauses for the production of diploid males and their performance in ahighly inbred social Hymenopteran species. In the ant Hypoponera opacior,inbreeding occurs between wingless sexuals, which mate within themother nest, whereas winged sexuals outbreed dur…