Based on the genetic inheritance and segregation of random amplified polymorphism DNA(RAPDs) markers,the analysis of linkage groups for birch was performed by using a pseudo-testcross strategy.A segregating population...Based on the genetic inheritance and segregation of random amplified polymorphism DNA(RAPDs) markers,the analysis of linkage groups for birch was performed by using a pseudo-testcross strategy.A segregating population comprising of 79 progenies from the cross between Betula pendula and B.platyphylla was obtained.A set of 1 000 random oligonucleotide primers were screened,and 178 primers were selected to generate RAPD markers within a sample of 79 F\-1 progenies.A total of 296 segregating sites was identified.Among them,273 sites belonged to 1∶1 segregating site,and 36 sites were found distorted from the 1∶1 ratio.The 273 sites segregating 1∶1(testcross configuration) were used to construct parent-specific linkage group,among which 137 sites were found for B.pendula and 136 sites for B.platyphylla.The resulting linkage maps consisted of 117 marker sites in 12 groups(four or more sites per group),2 triples and 3 pairs for B.pendula,which covered the map distance about 1 533.3 cM(Kosambi units),and the average map distance between adjacent markers was 16.4 cM.In the B.platyphylla,162 linked marker sites were integrated into 12 groups(four or more sites per group),2 triples and 4 pairs,which covered the map distance about 1 847.8 cM,and the average map distance between adjacent markers was 19.2 cM.The calculated genome coverage rate of B.pendula and B.platyphylla were respectively 68.5% and 68.9%.Further study is required to integrate the two maps to one density map and to locate important genes on the maps.展开更多
With a ＂two-way pseudo-testcross＂ mapping strategy, we applied the amplified fragment length polymorphism （AFLP） markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were ...With a ＂two-way pseudo-testcross＂ mapping strategy, we applied the amplified fragment length polymorphism （AFLP） markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F1 cross family （Laminaria iongissima Aresch. × L. Japonica Miyabe） with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1：1 ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3：1 Mendelian segregation ratio. Among the loci with 1：1 segregating ratios, 79 loci were ordered in 14 linkage groups （648.6 cM） of the paternal map, and 72 loci were ordered in 14 linkage groups （601.9 cM） of the maternal map. The average density of loci was approximately 1 per 8 cM. To Investigate the homologies between two parental maps, we used 58 loci segregated 3：1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.展开更多
文摘Based on the genetic inheritance and segregation of random amplified polymorphism DNA(RAPDs) markers,the analysis of linkage groups for birch was performed by using a pseudo-testcross strategy.A segregating population comprising of 79 progenies from the cross between Betula pendula and B.platyphylla was obtained.A set of 1 000 random oligonucleotide primers were screened,and 178 primers were selected to generate RAPD markers within a sample of 79 F\-1 progenies.A total of 296 segregating sites was identified.Among them,273 sites belonged to 1∶1 segregating site,and 36 sites were found distorted from the 1∶1 ratio.The 273 sites segregating 1∶1(testcross configuration) were used to construct parent-specific linkage group,among which 137 sites were found for B.pendula and 136 sites for B.platyphylla.The resulting linkage maps consisted of 117 marker sites in 12 groups(four or more sites per group),2 triples and 3 pairs for B.pendula,which covered the map distance about 1 533.3 cM(Kosambi units),and the average map distance between adjacent markers was 16.4 cM.In the B.platyphylla,162 linked marker sites were integrated into 12 groups(four or more sites per group),2 triples and 4 pairs,which covered the map distance about 1 847.8 cM,and the average map distance between adjacent markers was 19.2 cM.The calculated genome coverage rate of B.pendula and B.platyphylla were respectively 68.5% and 68.9%.Further study is required to integrate the two maps to one density map and to locate important genes on the maps.
文摘With a ＂two-way pseudo-testcross＂ mapping strategy, we applied the amplified fragment length polymorphism （AFLP） markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F1 cross family （Laminaria iongissima Aresch. × L. Japonica Miyabe） with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1：1 ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3：1 Mendelian segregation ratio. Among the loci with 1：1 segregating ratios, 79 loci were ordered in 14 linkage groups （648.6 cM） of the paternal map, and 72 loci were ordered in 14 linkage groups （601.9 cM） of the maternal map. The average density of loci was approximately 1 per 8 cM. To Investigate the homologies between two parental maps, we used 58 loci segregated 3：1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.
