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941.
W. R. Scowcroft P. J. Larkin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1981,60(3):179-184
Summary Plants were regenerated following intraspecific fusion of leaf protoplasts from two naturally occurring genotypes of Nicotiana debneyi. The two genotypes differed in the EcoRl fragmentation pattern of chloroplast DNA and in the nuclear-coded phosphoglucomutase (Pgm) isozymes. There was no conscious selection for hybrid genotypes during protoplast culture or plant regeneration. Among 225 plants screened for Pgm, six were identified as nuclear hybrids. Restriction endonuclease and filter hybridisation analysis revealed that the cytoplasms of the hybrids contained one or other but never both parental chloroplast DNAs. The sorting out of chloroplasts was random and complete; the limit of detecting a rare chloroplast-DNA type in a mixture was 0.1%. 相似文献
942.
H. Van Dijk 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,77(5):749-759
Summary Twelve Plantago major plants, good representatives of their populations, appeared to be genetically different for several characters which are important for adaptation to the respective habitat conditions. These characters are: juvenile growth, leaf morphology, production of secondary rosettes, flowering time, seed production, seed size and adult leaf production. The adaptive value of some of these characters was investigated by transplantation experiments in the field and by intraspecific competition experiments. The roadside type of ssp. major was adapted to trampling by being erect and elastic. The lawn type of ssp. major was adapted to a short, frequently cut, vegetation by being prostrate and by producing leaves with short petioles throughout the growth season. In the natural situations in which ssp. pleiosperma occurs, growth rate and first-year seed production of this subspecies were considerably higher than that of ssp. major. In a number of experiments, F1s and F2s were included, derived from crosses between the original plants. The F1s were generally rather well adapted to both parental habitats, whereas the F2s appeared to be less fit. The various alternatives in spending resources relevant for fitness optimization in different habitats are discussed.Grassland Species Research Group Publication No. 93 相似文献
943.
Genetic Regulation of Liver Microsomal CYP2E1 Activity among Strains of the Viviparous Fishes Poeciliopsis occidentalis and Poeciliopsis lucida 总被引:2,自引:0,他引:2
Lisa A. E. Kaplan Eileen Fielding Joseph F. Crivello 《Environmental Biology of Fishes》1999,54(3):337-343
The use of CYP2E1 (cytochrome P4502E1) expression as a biomarker for xenobiotic contamination may be useful, but for full understanding of the response, components of inheritance need to be understood. CYP2E1 expression was examined in P. lucida (M61-31), two strains of P. occidentalis (V87-15 and AV76-7), and their F1, F2, and backcross progeny. Phenotypic expression of CYP2E1 in Poeciliopsis has two distinct components – maximal activity and temperature optimum (T0) (Kaplan et al. 1991). In all P. occidentalis and P. lucida crosses, CYP2E1 activity segregated in up to three phenotypic groups. In F1 individuals (P. lucida×P. occidentalis V87-15), an overdominant phenotype was generated in 50% of the progeny. The P. lucida phenotype was absent suggesting a maternal effect on the F1 phenotype. Backcrosses of these F1 progeny to P. lucida females resulted in a recovery of the P. lucida phenotype while maintaining expression of an overdominant phenotype in 50% of the progeny. Among F2 progeny, an overdominant phenotype was expressed less often as compared to the F1 generation, and parental phenotypes were observed in equal numbers. Phenotypic expression patterns of CYP2E1 activity among F1 fish changed significantly with replacement of P. occidentalis V87-15 by P. occidentalis AV76-7. The P. lucida and P. occidentalis phenotype was equally distributed among progeny without evidence of an overdominant phenotype. Backcrosses of F1 progeny to P. lucida females resulted in equal amounts of the parental phenotypes. Backcross of an F1 male to a P. occidentalis AV76-7 female increased the P. occidentalis phenotype at the expense of the P. lucida phenotype in resulting progeny. Backcross of a F1 female to a P. lucida male resulted in equal distribution of the parental phenotypes. In addition, a greater number of F2 fish expressed the P. occidentalis phenotype as compared to the P. lucida phenotype. No significant difference in the sex ratios was seen in any of the crosses with the exception of one backcross. 相似文献
944.
A mitochondrial DNA character set based on cytochrome b gene variations is described that may be used in conjunction with established nuclear gene differences to assess largemouth bass Micropterus salmoides population structure and dynamics. Alignment of known cytochrome b sequences revealed two regions where the functional constraints of the molecule appear to be sufficiently reduced to allow several amino acid substitutions. Restriction analysis was used to probe nucleotide variation within one of these evolutionary hotspots, resulting in the discovery of fixed largemouth bass subspecific cytochrome b haplotypes. Application of two molecular character sets, one founded on fixed allelic variation in nuclear genes and the other on mtDNA cytochrome b diversity, revealed that in several Texas populations, where the Florida subspecies was introduced into extant populations of northern largemouth bass, hybridization was evident. The direction of the introgression vector could be determined through the combination of both character Sets. 相似文献
945.
Rie Shimizu-Inatsugi Silvija Milosavljevic Kentaro K. Shimizu Gabriela Schaepman-Strub Keitaro Tanoi Yasuhiro Sato 《Plant Species Biology》2021,36(2):208-217
Excessive amounts of metal ions in soil are toxic for most plant species, yet metal can also facilitate plant survival by elemental defense against herbivores and pathogens. Zinc and cadmium hyperaccumulation in Arabidopsis halleri is known to be effective for the defense against natural enemies. The allotetraploid species A. kamchatica, derived from A. halleri and a non-hyperaccumulator A. lyrata, has a lower hyperaccumulation level of zinc than A. halleri, but its significance for elemental defense remains unknown. In this study, we evaluated the accumulation levels of zinc and cadmium in the allotetraploid compared with its diploid progenitors, and evaluated the contribution of metal treatments to anti-herbivore resistance under field conditions. The accumulation level of zinc in A. kamchatica was intermediate between the progenitors, but that of cadmium was lower than in both diploid progenitors. The elemental defense of A. kamchatica and A. halleri was supported by a field experiment comparing the herbivory level between a control group and metal-supplemented plants. Moreover, the effect of elemental defense was lower in A. kamchatica than in the hyperaccumulator progenitor A. halleri, which is consistent with the metal accumulation level. This result reveals that the allotetraploid plant inherited its hyperaccumulating ability from one progenitor as an advantageous trait but at an intermediate level. 相似文献
946.
When the cotyledons of Pisum sativum are cultured in the presence of 2–4D, large populations of cells with polytene chromosomes are stimulated to enter prophase; the use of these chromosome for studies of in situ hybridisation with nucleic acids is described. 相似文献
947.
Matteo Schiavinato Alexandrina Bodrug-Schepers Juliane C. Dohm Heinz Himmelbauer 《The Plant journal : for cell and molecular biology》2021,106(3):672-688
Polyploidization is a well-known speciation and adaptation mechanism. Traces of former polyploidization events were discovered within many genomes, and especially in plants. Allopolyploidization by interspecific hybridization between two species is common. Among hybrid plants, many are domesticated species of agricultural interest and many of their genomes and of their presumptive parents have been sequenced. Hybrid genomes remain challenging to analyse because of the presence of multiple subgenomes. The genomes of hybrids often undergo rearrangement and degradation over time. Based on 10 hybrid plant genomes from six different genera, with hybridization dating from 10,000 to 5 million years ago, we assessed subgenome degradation, subgenomic intermixing and biased subgenome fractionation. The restructuring of hybrid genomes does not proceed proportionally with the age of the hybrid. The oldest hybrids in our data set display completely different fates: whereas the subgenomes of the tobacco plant Nicotiana benthamiana are in an advanced stage of degradation, the subgenomes of quinoa (Chenopodium quinoa) are exceptionally well conserved by structure and sequence. We observed statistically significant biased subgenome fractionation in seven out of 10 hybrids, which had different ages and subgenomic intermixing levels. Hence, we conclude that no correlation exists between biased fractionation and subgenome intermixing. Lastly, domestication may encourage or hinder subgenome intermixing, depending on the evolutionary context. In summary, comparative analysis of hybrid genomes and their presumptive parents allowed us to determine commonalities and differences between their evolutionary fates. In order to facilitate the future analysis of further hybrid genomes, we automated the analysis steps within manticore , which is publicly available at https://github.com/MatteoSchiavinato/manticore.git . 相似文献
948.
We describe and explain some of the changes in the fish community as reflected by the catches of the commercial fishery, and evaluate the efforts to restore the trout (Salvelinus spp.) in Georgian Bay. The changes in the fish community were caused in part by excessive fishing for lake trout (S. namaycush), lake whitefish (Coregonus clupeaformis) and deepwater ciscoes (Coregonus spp.), and the introduction of new species such as sea lamprey (Petromyzon marinus), alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax) and salmonids (Oncorhynchus spp.). The most striking changes were the near extinction of the lake trout, reductions in lake herring (Coregonus artedii), deepwater ciscoes and lake whitefish, and the increase in abundance of smelt and alewife. In an effort to replace the loss of yield from the cold-water habitat, a fast growing and early maturing hybrid trout (splake [S. namaycush × S. fontinalis]) and its backcross to lake trout were selectively bred for stocking in Georgian Bay. Splake did poorly because of low survival immediately after planting. The survival of backcross after planting was better, but adult mortality was still high. Adult survival of backcross improved considerably after restrictions were placed on the commercial fishery in 1984. The first naturally produced backcross larvae were collected in 1985. 相似文献
949.
Temporal analyses were applied to the tone pulses within the courtship songs of Drosophila melanogaster, D. simulans,their interspecific hybrid, and behavioral mutants of D. melanogaster.Linear regression was performed on various parameters of the song pulses (cycles per pulse, absolute peak amplitude, intrapulse frequency, number of peaks in fast Fourier transform, width of the primary frequency peak, and interpulse interval), as a function of their positions within pulse trains. Significant differences in the slope values of these two species and of the mutant genotypes allowed for discriminative quantification of temporal changes within trains. These results are discussed in relation to previous kinds of temporal analyses of Drosophilacourtship songs and also with regard to the mechanisms of song production. 相似文献
950.
Summary. Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species. 相似文献