RFLP mapping in Brassica nigra indicates differing recombination rates in male and female meioses

Genome ◽  
1995 ◽  
Vol 38 (2) ◽  
pp. 255-264 ◽  
Author(s):  
Ulf Lagercrantz ◽  
Derek J. Lydiate
Keyword(s):  
Sex Differences ◽  
Linkage Map ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Brassica Nigra ◽  
Recurrent Parent ◽  
Linkage Groups ◽  
Recombination Rates ◽  
Male Recombination ◽  
Male And Female

A genetic linkage map of Brassica nigra, comprised of 288 loci in eight linkage groups, was constructed. The linkage groups varied in size from 72 to 159 cM and the total map length was 855 cM. The recurrent parent used in the backcross was extremely heterozygous. This allowed recombination to be estimated separately for female (recurrent parent) meiosis and male (F1) meiosis over a large proportion of the genome. Significant differences between male and female recombination frequencies were observed on all six linkage groups where data was available for both sexes. Enhanced male recombination frequencies were observed that were associated with proterminal regions, while enhanced female recombination frequencies were adjacent to putative centromeres. It is possible that the distinct genotypes of the F1 (male) and recurrent (female) parents contributed to the observed differences in recombination. However, this study emphasizes the need to consider potential sex differences, in both the rate and the position of recombination, when planning genetic experiments and breeding programmes.Key words: genetic map, sex dependent recombination, centromeres, telomeres.

A genetic linkage map for Arctic char (Salvelinus alpinus): evidence for higher recombination rates and segregation distortion in hybrid versus pure strain mapping parents

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 304-315 ◽  
Author(s):  
R A Woram ◽  
C McGowan ◽  
J A Stout ◽  
K Gharbi ◽  
M M Ferguson ◽  
...  
Keyword(s):  
Linkage Map ◽  
Segregation Distortion ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Salvelinus Alpinus ◽  
Linkage Groups ◽  
Recombination Rates ◽  
Pure Strain ◽  
Female Hybrid ◽  
Map Distance

We constructed a genetic linkage map for Arctic char (Salvelinus alpinus) using two backcrosses between genetically divergent strains. Forty-six linkage groups (expected = 39–41) and 19 homeologous affinities (expected = 25) were identified using 184 microsatellites, 129 amplified fragment length polymorphisms (AFLPs), 13 type I gene markers, and one phenotypic marker, SEX. Twenty-six markers remain unlinked. Female map distance (9.92 Morgans) was substantially higher than male map distance (3.90 Morgans) based on the most complete parental information (i.e., the F1 hybrids). Female recombination rates were often significantly higher than those of males across all pairwise comparisons within homologous chromosomal segments (average female to male ratios within families was 1.69:1). The female hybrid parent had significantly higher recombination rates than the pure strain female parent. Segregation distortion was detected in four linkage groups (4, 8, 13, 20) for both families. In family 3, only the largest fish were sampled for genotyping, suggesting that segregation distortion may represent regions possessing influences on growth. In family 2, almost all cases showing segregation distortion involved markers in the female hybrid parent.Key words: salmonid fishes, polyploidy, homeology, genetic markers.

The First Comprehensive Genetic Linkage Map of a Marsupial: The Tammar Wallaby (Macropus eugenii)

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 321-330 ◽  
Author(s):  
Kyall R Zenger ◽  
Louise M McKenzie ◽  
Desmond W Cooper
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Average Distance ◽  
Tammar Wallaby ◽  
Chromosome 1 ◽  
Linkage Groups ◽  
Recombination Rates ◽  
Macropus Eugenii ◽  
Significant Linkage

AbstractThe production of a marsupial genetic linkage map is perhaps one of the most important objectives in marsupial research. This study used a total of 353 informative meioses and 64 genetic markers to construct a framework genetic linkage map for the tammar wallaby (Macropus eugenii). Nearly all markers (93.8%) formed a significant linkage (LOD > 3.0) with at least one other marker, indicating that the majority of the genome had been mapped. In fact, when compared with chiasmata data, >70% (828 cM) of the genome has been covered. Nine linkage groups were identified, with all but one (LG7; X-linked) allocated to the autosomes. These groups ranged in size from 15.7 to 176.5 cM and have an average distance of 16.2 cM between adjacent markers. Of the autosomal linkage groups (LGs), LG2 and LG3 were assigned to chromosome 1 and LG4 localized to chromosome 3 on the basis of physical localization of genes. Significant sex-specific distortions toward reduced female recombination rates were revealed in 22% of comparisons. When comparing the X chromosome data to closely related species it is apparent that they are conserved in both synteny and gene order.

scholarly journals Genetic Linkage Map of the Edible BasidiomycetePleurotus ostreatus

2000 ◽  
Vol 66 (12) ◽  
pp. 5290-5300 ◽  
Author(s):  
Luis M. Larraya ◽  
G�mer P�rez ◽  
Enrique Ritter ◽  
Antonio G. Pisabarro ◽  
Lucı́a Ramı́rez
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Gene Sequence ◽  
Genetic Linkage Map ◽  
Fragment Length Polymorphism ◽  
Individual Cell ◽  
Random Amplified Polymorphic Dna ◽  
Rrna Gene ◽  
Linkage Groups ◽  
Rrna Gene Sequence

ABSTRACT We have constructed a genetic linkage map of the edible basidiomycete Pleurotus ostreatus (var. Florida). The map is based on the segregation of 178 random amplified polymorphic DNA and 23 restriction fragment length polymorphism markers; four hydrophobin, two laccase, and two manganese peroxidase genes; both mating type loci; one isozyme locus (est1); the rRNA gene sequence; and a repetitive DNA sequence in a population of 80 sibling monokaryons. The map identifies 11 linkage groups corresponding to the chromosomes ofP. ostreatus, and it has a total length of 1,000.7 centimorgans (cM) with an average of 35.1 kbp/cM. The map shows a high correlation (0.76) between physical and genetic chromosome sizes. The number of crossovers observed per chromosome per individual cell is 0.89. This map covers nearly the whole genome of P. ostreatus.

A genetic linkage map for Stevia rebaudiana

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 657-661 ◽  
Author(s):  
Y Yao ◽  
M Ban ◽  
J Brandle
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Rapd Markers ◽  
Genetic Linkage Map ◽  
Average Distance ◽  
Stevia Rebaudiana ◽  
Linkage Groups ◽  
Genome Map ◽  
High Level ◽  
Map Distance

To lay a foundation for molecular breeding efforts, the first genetic linkage map for Stevia rebaudiana has been constructed using segregation data from a pseudo test-cross F1 population. A total of 183 randomly amplified polymorphic DNA (RAPD) markers were analysed and assembled into 21 linkage groups covering a total distance of 1389 cM, with an average distance between markers of of 7.6 cM. The 11 largest linkage groups consisted of 4-19 loci, ranged in length from 56 to 174 cM, and accounted for 75% of the total map distance. Fifteen RAPD loci were found to be unlinked. From the 521 primers showing amplification products, 185 (35.5%) produced a total of 293 polymorphic fragments, indicating a high level of genetic diversity in stevia. Most of the RAPD markers in stevia segregated in normal Mendelian fashion.Key words: stevia, open-pollinated, genome map, RAPD.

Mapping of quantitative trait loci underlying resistance to cassava anthracnose disease

2015 ◽  
Vol 154 (7) ◽  
pp. 1209-1217 ◽  
Author(s):  
A. BOONCHANAWIWAT ◽  
S. SRAPHET ◽  
S. WHANKAEW ◽  
O. BOONSENG ◽  
D. R. SMITH ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Linkage Map ◽  
Dna Markers ◽  
Quantitative Trait ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Gene Annotation ◽  
Linkage Groups ◽  
Anthracnose Disease ◽  
Trait Loci

SUMMARYCassava (Manihot esculenta Crantz) is an economically important root crop in Thailand, which is ranked the world's top cassava exporting country. Production of cassava can be hampered by several pathogens and pests. Cassava anthracnose disease (CAD) is an important disease caused by the fungus Colletotrichum gloeosporioides f. sp. manihotis. The pathogen causes severe stem damage resulting in yield reductions and lack of stem cuttings available for planting. Molecular studies of cassava response to CAD will provide useful information for cassava breeders to develop new varieties with resistance to the disease. The current study aimed to identify quantitative trait loci (QTL) and DNA markers associated with resistance to CAD. A total of 200 lines of two F1 mapping populations were generated by reciprocal crosses between the varieties Huabong60 and Hanatee. The F1 samples were genotyped based on simple sequence repeat (SSR) and expressed sequence tag-SSR markers and a genetic linkage map was constructed using the JoinMap®/version3·0 program. The results showed that the map consisted of 512 marker loci distributed on 24 linkage groups with a map length of 1771·9 centimorgan (cM) and a mean interval between markers of 5·7 cM. The genetic linkage map was integrated with phenotypic data for the response to CAD infection generated by a detached leaf assay test. A total of three QTL underlying the trait were identified on three linkage groups using the MapQTL®/version4·0 program. Those DNA markers linked to the QTL that showed high statistically significant values with the CAD resistance trait were identified for gene annotation analysis and 23 candidate resistance genes to CAD infection were identified.

scholarly journals Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene

Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 367-376 ◽  
Author(s):  
P.D. Olivera ◽  
A. Kilian ◽  
P. Wenzl ◽  
B.J. Steffenson
Keyword(s):  
Linkage Map ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Chromosomal Location ◽  
Dominant Gene ◽  
Leaf Rust Resistance Gene ◽  
Linkage Groups ◽  
Aegilops Sharonensis

Aegilops sharonensis (Sharon goatgrass), a diploid wheat relative, is known to be a rich source of disease resistance genes for wheat improvement. To facilitate the transfer of these genes into wheat, information on their chromosomal location is important. A genetic linkage map of Ae. sharonensis was constructed based on 179 F2 plants derived from a cross between accessions resistant (1644) and susceptible (1193) to wheat leaf rust. The linkage map was based on 389 markers (377 Diversity Arrays Technology (DArT) and 12 simple sequence repeat (SSR) loci) and was comprised of 10 linkage groups, ranging from 2.3 to 124.6 cM. The total genetic length of the map was 818.0 cM, with an average interval distance between markers of 3.63 cM. Based on the chromosomal location of 115 markers previously mapped in wheat, the four linkage groups of A, B, C, and E were assigned to Ae. sharonensis (Ssh) and homoeologous wheat chromosomes 6, 1, 3, and 2. The single dominant gene (designated LrAeSh1644) conferring resistance to leaf rust race THBJ in accession 1644 was positioned on linkage group A (chromosome 6Ssh) and was flanked by DArT markers wpt-9881 (at 1.9 cM distal from the gene) and wpt-6925 (4.5 cM proximal). This study clearly demonstrates the utility of DArT for genotyping uncharacterized species and tagging resistance genes where pertinent genomic information is lacking.

A genetic linkage map of tetraploid orchardgrass (Dactylis glomerata L.) and quantitative trait loci for heading date

Genome ◽  
2012 ◽  
Vol 55 (5) ◽  
pp. 360-369 ◽  
Author(s):  
Wengang Xie ◽  
Joseph G. Robins ◽  
B. Shaun Bushman
Keyword(s):  
Quantitative Trait Loci ◽  
Linkage Map ◽  
Quantitative Trait ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Heading Date ◽  
Dactylis Glomerata ◽  
Linkage Groups ◽  
Trait Loci ◽  
Dactylis Glomerata L

Orchardgrass ( Dactylis glomerata L.), or cocksfoot, is indigenous to Eurasia and northern Africa, but has been naturalized on nearly every continent and is one of the top perennial forage grasses grown worldwide. To improve the understanding of genetic architecture of orchardgrass and provide a template for heading date candidate gene search in this species, the goals of the present study were to construct a tetraploid orchardgrass genetic linkage map and identify quantitative trait loci associated with heading date. A combination of SSR markers derived from an orchardgrass EST library and AFLP markers were used to genotype an F1 population of 284 individuals derived from a very late heading Dactylis glomerata subsp. himalayensis parent and an early to mid-heading Dactylis glomerata subsp. aschersoniana parent. Two parental maps were constructed with 28 cosegregation groups and seven consensus linkage groups each, and homologous linkage groups were tied together by 38 bridging markers. Linkage group lengths varied from 98 to 187 cM, with an average distance between markers of 5.5 cM. All but two mapped SSR markers had homologies to physically mapped rice (Oryza sativa L.) genes, and six of the seven orchardgrass linkage groups were assigned based on this putative synteny with rice. Quantitative trait loci were detected for heading date on linkage groups 2, 5, and 6 in both parental maps, explaining between 12% and 24% of the variation.

Linkage of random amplified polymorphic DNA, isozyme and morphological markers in grasspea (Lathyrus sativus)

1999 ◽  
Vol 133 (4) ◽  
pp. 389-395 ◽  
Author(s):  
M. A. CHOWDHURY ◽  
A. E. SLINKARD
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Rapd Markers ◽  
Genetic Linkage Map ◽  
Average Distance ◽  
Random Amplified Polymorphic Dna ◽  
Lathyrus Sativus ◽  
Morphological Markers ◽  
Linkage Studies ◽  
Linkage Groups

We constructed a genetic linkage map of grasspea (Lathyrus sativus L.; 2n = 14) from 100 F2 individuals derived from a cross between PI 426891.1.3 and PI 283564c.3.2. A total of 71 RAPD, three isozyme and one morphological markers segregated in the F2 progeny. A small fraction of markers (12%) deviated significantly from the expected Mendelian ratio (1[ratio ]2[ratio ]1 or 3[ratio ]1). Out of 75 markers, 69 (one morphological, three isozyme and 65 RAPD markers) were assigned to 14 linkage groups comprising 898 cM. The average distance between two adjacent markers was 17·2 cM. The present linkage map will serve as a reference point for further linkage studies in grasspea.

A molecular genetic linkage map identifying the St and H subgenomes of Elymus (Poaceae: Triticeae) wheatgrass

Genome ◽  
2011 ◽  
Vol 54 (10) ◽  
pp. 819-828 ◽  
Author(s):  
Ivan W. Mott ◽  
Steven R. Larson ◽  
Thomas A. Jones ◽  
Joseph G. Robins ◽  
Kevin B. Jensen ◽  
...  
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Molecular Genetic ◽  
Perennial Grass ◽  
Rice Genome ◽  
Backcross Progeny ◽  
Linkage Groups ◽  
Sts Markers ◽  
Snake River Wheatgrass

Elymus L. is the largest and most complex genus in the Triticeae tribe of grasses with approximately 150 polyploid perennial species occurring worldwide. We report here the first genetic linkage map for Elymus. Backcross mapping populations were created by crossing caespitose Elymus wawawaiensis (EW) (Snake River wheatgrass) and rhizomatous Elymus lanceolatus (EL) (thickspike wheatgrass) to produce F1 interspecific hybrids that were then backcrossed to the same EL male to generate progeny with segregating phenotypes. EW and EL are both allotetraploid species (n = 14) containing the St (Pseudoroegneria) and H (Hordeum) genomes. A total of 387 backcross progeny from four populations were genotyped using 399 AFLP and 116 EST-based SSR and STS markers. The resulting consensus map was 2574 cM in length apportioned among the expected number of 14 linkage groups. EST-based SSR and STS markers with homology to rice genome sequences were used to identify Elymus linkage groups homoeologous to chromosomes 1–7 of wheat. The frequency of St-derived genome markers on each linkage group was used to assign genome designations to all linkage groups, resulting in the identification of the seven St and seven H linkage groups of Elymus. This map also confirms the alloploidy and disomic chromosome pairing and segregation of Elymus and will be useful in identifying QTLs controlling perennial grass traits in this genus.

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