scholarly journals Inheritance and linkage analysis of co-dominant SSR markers on the Z chromosome of the silkworm (Bombyx mori L.)

2008 ◽  
Vol 90 (2) ◽  
pp. 151-156 ◽  
Author(s):  
XUE-XIA MIAO ◽  
WEI-HUA LI ◽  
MU-WANG LI ◽  
YUN-PO ZHAO ◽  
XIAN-RU GUO ◽  
...  
Keyword(s):  
Linkage Map ◽  
Bombyx Mori ◽  
Ssr Markers ◽  
Positional Cloning ◽  
Z Chromosome ◽  
Pcr Marker ◽  
Backcross Population ◽  
In The Beginning ◽  
Simple Sequence ◽  
Visible Mutation

SummaryMicrosatellites or simple sequence repeats (SSRs) are co-dominant molecular markers. When we used fluorescent SSR markers to construct a linkage map for the female heterogametic silkworm (Bombyx mori, ZW), we found that some loci did not segregate in a Mendelian ratio of 1:1 in a backcross population. These loci segregated in a 3:1 ratio of single bands compared with double bands. Further examination of band patterns indicated that three types of SSR bands were present: two homozygotes and one heterozygote. In the beginning, we considered to discard these markers. By scoring male and female F1 individuals, we confirmed that these loci were located on the Z chromosome. Using the sex-linked visible mutation sch (K05) and its wild-type (C108), we constructed an F1 male backcross (BC1M) mapping population. The combination of sch backcross and SSR data enabled us to map the SSR markers to the Z chromosome. By adjusting input parameters based on these data, we were able to use Mapmaker software to construct a linkage map. This strategy takes advantage of co-dominant markers for positional cloning of genes on the Z chromosome. We localized sch to the Z chromosome relative to six SSR markers and one PCR marker, covering a total of 76·1 cM. The sch mutation is an important sex-linked visible mutation widely used in breeding of commercial silkworms (e.g. male silkworm selection rearing). Localization of the sch gene may prove helpful in cloning the gene and developing strains for marker-assisted selection in silkworm breeding.

Genetic diversity among silkworm (Bombyx mori L., Lep., Bombycidae) germplasms revealed by microsatellites

Genome ◽  
2005 ◽  
Vol 48 (5) ◽  
pp. 802-810 ◽  
Author(s):  
Muwang Li ◽  
Li Shen ◽  
Anying Xu ◽  
Xuexia Miao ◽  
Chengxiang Hou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Bombyx Mori ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Genetic Relationships ◽  
Group Method ◽  
Sequence Repeat ◽  
Bombyx Mori L ◽  
Simple Sequence ◽  
Silkworm Bombyx Mori

To determine genetic relationships among strains of silkworm, Bombyx mori L., 31 strains with different origins, number of generations per year, number of molts per generation, and morphological characters were studied using simple sequence repeat (SSR) markers. Twenty-six primer pairs flanking microsatellite sequences in the silkworm genome were assayed. All were polymorphic and unambiguously separated silkworm strains from each other. A total of 188 alleles were detected with a mean value of 7.2 alleles/locus (range 2–17). The average heterozygosity value for each SSR locus ranged from 0 to 0.60, and the highest one was 0.96 (Fl0516 in 4013). The mean polymorphism index content (PIC) was 0.66 (range 0.12–0.89). Unweighted pair group method with arithmetic means (UPGMA) cluster analysis of Nei's genetic distance grouped silkworm strains based on their origin. Seven major ecotypic silkworm groups were analyzed. Principal components analysis (PCA) for SSR data support their UPGMA clustering. The results indicated that SSR markers are an efficient tool for fingerprinting cultivars and conducting genetic-diversity studies in the silkworm.Key words: silkworm, Bombyx mori L., microsatellites, simple sequence repeat (SSR), genetic diversity.

scholarly journals Linkage and mapping analyses of the no glue egg gene Ng in the silkworm (Bombyx mori L.) using simple sequence repeats (SSR) markers

2011 ◽  
Vol 10 (47) ◽  
pp. 9549-9556 ◽  
Author(s):  
Zhao Xiao ming ◽  
Wei Guo qing ◽  
Liu Chao liang ◽  
Zou Chang rui ◽  
Zhu Bao jian
Keyword(s):  
Bombyx Mori ◽  
Ssr Markers ◽  
Simple Sequence Repeats ◽  
Bombyx Mori L ◽  
Simple Sequence ◽  
Silkworm Bombyx Mori

scholarly journals A Dense Genetic Map of the Silkworm, Bombyx mori, Covering All Chromosomes Based on 1018 Molecular Markers

Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1513-1525 ◽  
Author(s):  
Yuji Yasukochi
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Markers ◽  
Linkage Map ◽  
Bombyx Mori ◽  
Genetic Markers ◽  
Genetic Map ◽  
Z Chromosome ◽  
Linkage Groups ◽  
Average Interval ◽  
Silkworm Bombyx Mori

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.

A reference cross DNA panel for zebrafish (Danio rerio) anchored with simple sequence length polymorphisms

Development ◽  
1996 ◽  
Vol 123 (1) ◽  
pp. 451-460 ◽  
Author(s):  
E.W. Knapik ◽  
A. Goodman ◽  
O.S. Atkinson ◽  
C.T. Roberts ◽  
M. Shiozawa ◽  
...  
Keyword(s):  
Linkage Map ◽  
Genetic Markers ◽  
Genetic Linkage ◽  
Positional Cloning ◽  
Genetic Linkage Map ◽  
Physical Map ◽  
Sequence Length ◽  
Mapping Tool ◽  
Length Polymorphisms ◽  
Simple Sequence

The ultimate informativeness of the zebrafish mutations described in this issue will rest in part on the ability to clone these genes. However, the genetic infrastructure required for the positional cloning in zebrafish is still in its infancy. Here we report a reference cross panel of DNA, consisting of 520 F2 progeny (1040 meioses) that has been anchored to a zebrafish genetic linkage map by 102 simple sequence length polymorphisms. This reference cross DNA provides: (1) a panel of DNA from the cross that was used to construct the genetic linkage map, upon which polymorphic gene(s) and genetic markers can be mapped; (2) a fine order mapping tool, with a maximum resolution of 0.1 cM; and (3) a foundation for the development of a physical map (an ordered array of clones each containing a known portion of the genome). This reference cross DNA will serve as a resource enabling investigators to relate genes or genetic markers directly to a single genetic linkage map and avoid the problem of integrating different maps with different genetic markers, as must be currently done when using randomly amplified polymorphic DNA markers, or as has occurred with human genetic linkage maps.

A genetic linkage map for hazelnut (Corylus avellana L.) based on RAPD and SSR markers

Genome ◽  
2006 ◽  
Vol 49 (2) ◽  
pp. 122-133 ◽  
Author(s):  
Shawn A Mehlenbacher ◽  
Rebecca N Brown ◽  
Eduardo R Nouhra ◽  
Tufan Gökirmak ◽  
Nahla V Bassil ◽  
...  
Keyword(s):  
Linkage Map ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Random Amplified Polymorphic Dna ◽  
Corylus Avellana ◽  
Sequence Repeat ◽  
Starting Point ◽  
Ssr Loci ◽  
Corylus Avellana L ◽  
Simple Sequence

A linkage map for European hazelnut (Corylus avellana L.) was constructed using random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers and the 2-way pseudotestcross approach. A full-sib population of 144 seedlings from the cross OSU 252.146 × OSU 414.062 was used. RAPD markers in testcross configuration, segregating 1:1, were used to construct separate maps for each parent. Fifty additional RAPD loci were assigned to linkage groups as accessory markers whose exact location could not be determined. Markers in intercross configuration, segregating 3:1, were used to pair groups in one parent with their homologues in the other. Eleven groups were identified for each parent, corresponding to the haploid chromosome number of hazelnut (n = x = 11). Thirty of the 31 SSR loci were able to be assigned to a linkage group. The maternal map included 249 RAPD and 20 SSR markers and spanned a distance of 661 cM. The paternal map included 271 RAPD and 28 SSR markers and spanned a distance of 812 cM. The maps are quite dense, with an average of 2.6 cM between adjacent markers. The S-locus, which controls pollen-stigma incompatibility, was placed on chromosome 5S where 6 markers linked within a distance of 10 cM were identified. A locus for resistance to eastern filbert blight, caused by Anisogramma anomala, was placed on chromosome 6R for which two additional markers tightly linked to the dominant allele were identified and sequenced. These maps will serve as a starting point for future studies of the hazelnut genome, including map-based cloning of important genes. The inclusion of SSR loci on the map will make it useful in other populations.Key words: Corylus avellana, hazelnut, filbert, linkage map, pseudotestcross, pollen-stigma incompatibility, random amplified polymorphic DNA, simple sequence repeat, microsatellite.

scholarly journals Construction of a genetic linkage map of cigar tobacco (Nicotiana tabacum L.) based on SSR markers and comparative studies

2018 ◽  
Vol 54 (No. 3) ◽  
pp. 115-122 ◽  
Author(s):  
Tong Zhijun ◽  
Xiao Bingguang ◽  
Chen Xuejun ◽  
Fang Dunhuang ◽  
Zhang Yihan ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Nicotiana Tabacum ◽  
Linkage Map ◽  
Ssr Markers ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Average Distance ◽  
Backcross Population ◽  
Breeding Programs ◽  
Nicotiana Tabacum L

Genetic linkage maps representing the tobacco genome have been an important tool for breeding programs because of the elucidation of polygenic traits. We constructed a genetic linkage map of cigar tobacco (Nicotiana tabacum L.) based on an inter-type backcross population of 213 individuals and performed a comparative analysis with other published maps of dark tobacco and flue-cured tobacco. The map consisted of 562 SSR loci distributed on 24 tentative linkage groups and spanned a total length of 1341.18 cM with an average distance of 2.39 cM between adjacent markers. The comparative analysis revealed a Spearman correlation index of 0.93 for marker order conservation with the previously published maps constructed for different tobacco types. Approximately 91% of the SSR markers common to other inter-type maps were located in the same positions as in previous maps. The three maps exhibit good synteny in terms of the shared markers, which suggests that there might be no translocation variations between the genomes of the cigar, dark and flue-cured tobaccos. These results indicate the feasibility of generating a unique genetic map of preferred traits in cigar tobacco and that such mapping may be helpful for breeding programs because plants derived from different inter-type populations can be rapidly scanned using the markers associated with useful cigar traits

scholarly journals Simple sequence repeat-based consensus linkage map of Bombyx mori

2005 ◽  
Vol 102 (45) ◽  
pp. 16303-16308 ◽  
Author(s):  
X.-X. Miao ◽  
S.-J. Xub ◽  
M.-H. Li ◽  
M.-W. Li ◽  
J.-H. Huang ◽  
...  
Keyword(s):  
Linkage Map ◽  
Bombyx Mori ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Simple Sequence
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