A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total ...A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total of 14 788 SSRs were observed in the whole genomic DNA sequence, about one every 2.57 kb, with the criteria of SSR length >15 bp and 80% matches. The most abundant microsatellite was trinucleotide repeat, the number was 4 729, followed by hexanucleotide and mononucleotide repeats, the numbers were 2 940 and 2 489 respectively, and the least abundance was dinucleotide repeat, only 691 were found. Among the 10 082 ORFs, 4 094 SSRs were harbored in 2 373 ORF (no intron) of the organism. One thousand and fifty six ORFs harbored only one SSR. Similar with other organisms, tri- and hexanucleotide repeats were predominant in ORFs, 54.1 and 48.8% of tri- and hexanucleotide repeats were distributed in ORF region. The density of these two motifs was overpresented in coding regions, because ORF region and coding region constitutes only 46 and 38.3% of genomic sequence, respectively. Upstream and downstream 300 bp of regulatory regions were high density regions of SSRs, particularly density of pentanucleotide SSR in upstream region was as high as five times of average density in genomic DNA, density of di- and tetranucleotide SSR was also more than two times of average density. The density of penta-, tetra-, di- and mononucleotide SSRs was relatively higher than average density. There were 47 SSRs in mitochondria 64 840 bp DNA sequence, their distribution is similar with genomic DNA sequence. These results suggested that SSRs were clustered in regulatory regions of genomic DNA.展开更多
Specific-locus mutations induced in the ad-3region of two-component heterokaryons ofNeurospora have been compared by means ofMutational Spectra.Genetic characterization ofad-3 mutations has revealed that there are maj...Specific-locus mutations induced in the ad-3region of two-component heterokaryons ofNeurospora have been compared by means ofMutational Spectra.Genetic characterization ofad-3 mutations has revealed that there are majorclasses:gene/point mutations,multilocus deletionmutations and unknowns (mutants that grow toorapidly alone on minimal medium to be classified).展开更多
Since Wilson and Ross （1962） bred wheat male sterile line with T. timopheevi cytoplasm （G type） and its relative restoration line, with high utilization value, the progress has been accelerated in research of hete...Since Wilson and Ross （1962） bred wheat male sterile line with T. timopheevi cytoplasm （G type） and its relative restoration line, with high utilization value, the progress has been accelerated in research of heterotic use of wheat male sterility. But so far they have not been used in large area production, because of the limited restorer resource, imperfect grains and insignificant population heterosis. Ae（?）ilops kotschyi and Ae. Variabilis types/（S<sup>v</sup> type） overcame well some problems in G type, such as restorer resource, grain plumpness etc., but at the same time, other more difficult problems arose, e. g. their sterile line and hybrid F<sub>1</sub> generation produced monoploids at a certain rate, hybrid growth was weak and restorer degree of sterility had a large variation scale. The stability of sterility in Ae. Ventricosa （D type） and Ae unianstata （Mu type） cytoplasms, as well as the maintenance and restoration of their male sterile lines were further studied. In order展开更多
基金the National Natural Science Foundation of China(30360061) Natural Science Foundation of Yunnan Province of China(1999一c0008z).
文摘A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total of 14 788 SSRs were observed in the whole genomic DNA sequence, about one every 2.57 kb, with the criteria of SSR length >15 bp and 80% matches. The most abundant microsatellite was trinucleotide repeat, the number was 4 729, followed by hexanucleotide and mononucleotide repeats, the numbers were 2 940 and 2 489 respectively, and the least abundance was dinucleotide repeat, only 691 were found. Among the 10 082 ORFs, 4 094 SSRs were harbored in 2 373 ORF (no intron) of the organism. One thousand and fifty six ORFs harbored only one SSR. Similar with other organisms, tri- and hexanucleotide repeats were predominant in ORFs, 54.1 and 48.8% of tri- and hexanucleotide repeats were distributed in ORF region. The density of these two motifs was overpresented in coding regions, because ORF region and coding region constitutes only 46 and 38.3% of genomic sequence, respectively. Upstream and downstream 300 bp of regulatory regions were high density regions of SSRs, particularly density of pentanucleotide SSR in upstream region was as high as five times of average density in genomic DNA, density of di- and tetranucleotide SSR was also more than two times of average density. The density of penta-, tetra-, di- and mononucleotide SSRs was relatively higher than average density. There were 47 SSRs in mitochondria 64 840 bp DNA sequence, their distribution is similar with genomic DNA sequence. These results suggested that SSRs were clustered in regulatory regions of genomic DNA.
文摘Specific-locus mutations induced in the ad-3region of two-component heterokaryons ofNeurospora have been compared by means ofMutational Spectra.Genetic characterization ofad-3 mutations has revealed that there are majorclasses:gene/point mutations,multilocus deletionmutations and unknowns (mutants that grow toorapidly alone on minimal medium to be classified).
基金Project supported by the Eighth Five-Year Planthe National Basis Science-Scaled Plan
文摘Since Wilson and Ross （1962） bred wheat male sterile line with T. timopheevi cytoplasm （G type） and its relative restoration line, with high utilization value, the progress has been accelerated in research of heterotic use of wheat male sterility. But so far they have not been used in large area production, because of the limited restorer resource, imperfect grains and insignificant population heterosis. Ae（?）ilops kotschyi and Ae. Variabilis types/（S<sup>v</sup> type） overcame well some problems in G type, such as restorer resource, grain plumpness etc., but at the same time, other more difficult problems arose, e. g. their sterile line and hybrid F<sub>1</sub> generation produced monoploids at a certain rate, hybrid growth was weak and restorer degree of sterility had a large variation scale. The stability of sterility in Ae. Ventricosa （D type） and Ae unianstata （Mu type） cytoplasms, as well as the maintenance and restoration of their male sterile lines were further studied. In order
