Integration of molecular and classical linkage groups of the silkworm, Bombyx mori (n = 28)

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 626-629 ◽  
Author(s):  
Yuji Yasukochi ◽  
Yutaka Banno ◽  
Kohji Yamamoto ◽  
Marian R Goldsmith ◽  
Hiroshi Fujii

Previously published linkage groups (LGs) composed of molecular markers were assigned to classical LGs in the silkworm, Bombyx mori (n = 28). Four markers from the classical linkage map, og, w-1, Lp, and Pfl, were assigned to the molecular linkage maps using sequence tagged sites. In addition, linkage analysis was carried out using BF1 progeny between wild-type and mutant stocks carrying morphological phenotypic markers. As a result, the counterparts for 26 of 28 molecular LGs were identified with their counterparts of the classical LGs. Two visible markers, Sel and Xan, representing different classical LGs, were found to be linked.Key words: Bombyx mori, classical linkage group (LG), PCR-based genotyping, mutant, STS.

Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1513-1525 ◽  
Author(s):  
Yuji Yasukochi

Abstract A dense linkage map was constructed for the silkworm, Bombyx mori, containing 1018 genetic markers on all 27 autosomes and the Z chromosome. Most of the markers, covering ∼2000 cM, were randomly amplified polymorphic DNAs amplified with primer-pairs in combinations of 140 commercially available decanucleotides. In addition, eight known genes and five visible mutations were mapped. Bombyx homologues of engrailed and invected genes were found to be closely linked, as in Drosophila melanogaster. The average interval between markers was ∼2 cM, equal to ∼500 kb. The correspondence of seven linkage groups to counterparts of the conventional linkage map was determined. This map is the first linkage map in insects having a large number of chromosomes (n = 28) that covers all chromosomes without any gaps.


Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1277-1288
Author(s):  
Stephen L Johnson ◽  
Michael A Gates ◽  
Michele Johnson ◽  
William S Talbot ◽  
Sally Horne ◽  
...  

Abstract The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.


1995 ◽  
Vol 66 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Amornrat Promboon ◽  
Toru Shimada ◽  
Haruhiko Fujiwara ◽  
Masahiko Kobayashi

SummaryWe have constructed a linkage map of random amplified polymorphic DNAs (RAPDs) in Bombyx mori. We screened 320 10-mer primers, and found 243 clear polymorphic bands between C108 and p50 strains. In the F2 generation, segregation ratios of 168 bands were nearly 3:1 in a chi square test, showing Mendelian inheritance. The MAPMAKER program sorted 168 bands into 29 linkage groups and 10 unlinked loci at minimum LOD score 3·0, and determined orders of loci in each group, which contained 2–11 markers. It also detected typing errors in our data. We calculated map distances between pairs of neighbouring loci using recombination values in males and the Kosambi mapping function. Our RAPD map consists of 169 loci including the p locus, and the sum of map distances is approximately 900 cM. Linkage groups 1 and 2 of our map correspond to chromosomes 1 and 2 on the conventional linkage map because of linkage to sex and p, respectively.


2006 ◽  
Vol 3 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Sima Yang-Hu ◽  
Li Bin ◽  
Chen Da-Xia ◽  
Sun De-Bin ◽  
Zhao Ai-Chun ◽  
...  

AbstractAn amplification fragment length polymorphism (AFLP) molecular linkage map with a relatively high density for location of quantitative trait loci (QTLs) controlling the quantitative traits of silkworm (Bombyx mori) cocoons, was constructed using 91 individuals of the F2 generation. Among the 692 effective loci, 550 were allocated to subgroups a and b, of which 21 linkage groups in subgroup a had 233 molecular markers and 28 linkage groups in subgroup b had 317 markers. The number of markers on each linkage group in subgroups a and b ranged from 4 to 43 and 3 to 35, respectively. The total length of linkage groups for subgroup a was 1868.10 cM, and 2677.50 cM for subgroup b. The length of linkage group varied from 22.3 to 424.3 cM in subgroup a and from 2.4 to 366.5 cM in subgroup b. The average variation in the distance between markers was 3.39–17.43 cM in subgroup a and 0.8–26.96 cM in subgroup b. The average distance between the markers was 8.81 cM in subgroup a and 9.26 cM in subgroup b. There were 14 linkage groups, with an average distance below 10 cM, in subgroup a and 18 linkage groups in subgroup b. There were seven linkage groups with an average distance between 10 and 20 cM in subgroup a and ten linkage groups in subgroup b. Each linkage group in subgroup a had 11.1 loci on average, while there were 11.31 loci on each linkage group on average in subgroup b. The mean length for linkage groups in subgroups a and b was 89 and 95.6 cM, respectively. The total average length for both a and b subgroups was 2272.8, and 9.06 cM for the average marker distance, fulfilling the basic known requirements for locating QTLs.


Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 703-724 ◽  
Author(s):  
A M Crawford ◽  
K G Dodds ◽  
A J Ede ◽  
C A Pierson ◽  
G W Montgomery ◽  
...  

Abstract We report the first extensive ovine genetic linkage map covering 2070 cM of the sheep genome. The map was generated from the linkage analysis of 246 polymorphic markers, in nine three-generation full-sib pedigrees, which make up the AgResearch International Mapping Flock. We have exploited many markers from cattle so that valuable comparisons between these two ruminant linkage maps can be made. The markers, used in the segregation analyses, comprised 86 anonymous microsatellite markers derived from the sheep genome, 126 anonymous microsatellites from cattle, one from deer, and 33 polymorphic markers of various types associated with known genes. The maximum number of informative meioses within the mapping flock was 222. The average number of informative meioses per marker was 140 (range 18-209). Linkage groups have been assigned to all 26 sheep autosomes.


1995 ◽  
Vol 66 (2) ◽  
pp. 109-126 ◽  
Author(s):  
Jinrui Shi ◽  
David G. Heckel ◽  
Marian R. Goldsmith

SummaryWe present data for the initial construction of a molecular linkage map for the domesticated silkworm, Bombyx mori, based on 52 progeny from an F2 cross from a pair mating of inbred strains p50 and C108, using restriction fragment length polymorphisms (RFLPs). The map contains 15 characterized single copy sequences, 36 anonymous sequences derived from a follicular cDNA library, and 10 loci corresponding to a low copy number retrotransposon, mag. The 15 linkage groups and 8 ungrouped loci account for 23 of the 28 chromosomes and span a total recombination length of 413 cM; 10 linkage groups were correlated with established classic genetic maps. Scoring data from Southern blots were analysed using two Pascal programs written specifically to analyse linkage data in Lepidoptera, where females are the heterogametic sex and have achiasmatic meiosis (no crossing-over). These first examine evidence for linkage by calculating the maximum lod score under the hypothesis that the two loci are linked over the likelihood under the hypothesis that the two loci assort independently, and then determine multilocus linkage maps for groups of putatively syntenic loci by calculating the maximum likelihood estimate of the recombination fractions and the log likelihood using the EM algorithm for a specified order of loci along the chromosome. In addition, the possibility of spurious linkage was exhaustively tested by searching for genotypes forbidden by the absence of crossing-over in one sex.


2000 ◽  
Vol 51 (4) ◽  
pp. 415 ◽  
Author(s):  
C. J. Lambrides ◽  
R. J. Lawn ◽  
I. D. Godwin ◽  
J. Manners ◽  
B. C. Imrie

Two genetic linkage maps of mungbean derived from the cross Berken ACC 41 are reported. The F2 map constructed from 67 individuals consisted of 110 markers (52 RFLP and 56 RAPD) that grouped into 12 linkage groups. The linked markers spanned a total map distance of 758.3 cM. A recombinant inbred (RI) population derived from the 67 F2 individuals was used for the generation of an additional linkage map. The RI map, composed entirely of RAPD markers, consisted of 115 markers in 12 linkage groups. The linked markers spanned a total map distance of 691.7 cM. Using a framework set of RFLP markers, the F2 map was compared with another F2 mungbean map constructed in Minnesota. In general, the order of these markers was consistent between maps. Segregation distortion was observed for some markers. 14.5% (16/110) of mapped F2 markers and 24% (28/115) of mapped RI markers segregated with distorted ratios. Segregation distortion occurred in each successive generation after the F2 . The regions of distortion identified in the Australian maps did not coincide with regions of the Minnesota map.


1972 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Anne McVittie

SUMMARYEight newly isolated 9 + 0 mutants each mapped at one of the four previously known loci. Short flagellum mutants were at three loci, two of which (pf7 and pf8) were closely linked; the third, pf21, was unlinked to these two and mapped on linkage group II. The long flagellum mutants lf1 and lf2 were on linkage groups II and XII respectively. Mutants pf8A and lf1 were both recessive to wild-type. There was no evidence for non-Mendelian flagellum mutants.


Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 783-790 ◽  
Author(s):  
Maria Teresa Dettori ◽  
Roberta Quarta ◽  
Ignazio Verde

A linkage map was obtained using a BC1 progeny (Prunus persica × (P. persica × P. ferganensis)). The map is composed of 109 loci (74 RFLPs, 17 SSRs, 16 RAPDs, and two morphological traits) distributed in 10 linkage groups. Loci, segregating in five different ratios, were integrated in the map with JoinMap 2.0 software. The map covers 521 cM of the peach genome. The average distance between adjacent loci is 4.8 cM. Two monogenic traits, flesh adhesion (F/f) and leaf glands (E/e), were placed on the map. Thirty-two loci in common with a saturated linkage map of Prunus allowed a comparative analysis to be made between the two maps. Homologies were found among the respective linkage groups. No relevant differences were observed in the linear order of the common loci.Key words: peach, linkage map, Prunus persica, Prunus ferganensis, molecular markers.


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