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.

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.

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.

scholarly journals A second-generation anchored genetic linkage map of the tammar wallaby (Macropus eugenii)

BMC Genetics ◽  
2011 ◽  
Vol 12 (1) ◽  
pp. 72 ◽  
Author(s):  
Chenwei Wang ◽  
Lee Webley ◽  
Ke-jun Wei ◽  
Matthew J Wakefield ◽  
Hardip R Patel ◽  
...  
Keyword(s):  
Linkage Map ◽  
Genetic Linkage ◽  
Second Generation ◽  
Genetic Linkage Map ◽  
Tammar Wallaby ◽  
Macropus Eugenii

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.

A genetic linkage map in autotetraploid lucerne adapted to northern Australia, and use of the map to identify DNA markers linked to resistance to Phytophthora medicaginis

2005 ◽  
Vol 56 (4) ◽  
pp. 333 ◽  
Author(s):  
J. M. Musial ◽  
K. S. Aitken ◽  
J. M. Mackie ◽  
J. A. G. Irwin
Keyword(s):  
Linkage Map ◽  
Phenotypic Variation ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Average Distance ◽  
Linkage Groups ◽  
Resistance Qtls ◽  
Backcross Population ◽  
Resistant Parent ◽  
Repulsion Phase

Phytophthora root rot, caused by Phytophthora medicaginis, is a major limitation to lucerne (Medicago sativa L.) production in Australia and North America. Quantitative trait loci (QTLs) involved in resistance to P. medicaginis were identified in a lucerne backcross population of 120 individuals. A genetic linkage map was constructed for tetraploid lucerne using 50 RAPD (randomly amplified polymorphic DNA), 104 AFLP (amplified fragment length polymorphism) markers, and one SSR (simple sequence repeat or microsatellite) marker, which originated from the resistant parent (W116); 13 markers remain unlinked. The linkage map contains 18 linkage groups covering 2136.5 cM, with an average distance of 15.0 cM between markers. Four of the linkage groups contained only either 2 or 3 markers. Using duplex markers and repulsion phase linkages the map condensed to 7 homology groups and 2 unassigned linkage groups. Three regions located on linkage groups 2, 14, and 18, were identified as associated with root reaction and the QTLs explained 6–15% of the phenotypic variation. The research also indicates that different resistance QTLs are involved in conferring resistance in different organs. Two QTLs were identified as associated with disease resistance expressed after inoculation of detached leaves. The marker, W11-2 on group 18, identified as associated with root reaction, contributed 7% of the phenotypic variation in leaf response in our population. This marker appears to be linked to a QTL encoding a resistance factor contributing to both root and leaf reaction. One other QTL, not identified as associated with root reaction, was positioned on group 1 and contributed to 6% of the variation. This genetic linkage map provides an entry point for future molecular-based improvement of lucerne in Australia, and markers linked to the QTLs we have reported should be useful for marker-assisted selection for partial resistance to P. medicaginis in lucerne.

Constructing a genetic linkage map and mapping quantitative trait loci for skeletal traits in Japanese flounder

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Yi Liu ◽  
Yongxin Liu ◽  
Yingjie Liu ◽  
Xiaoyan Zhang ◽  
Fei Si ◽  
...  
Keyword(s):  
Linkage Map ◽  
Quantitative Trait ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Expressed Sequence Tag ◽  
Average Distance ◽  
Doubled Haploids ◽  
Japanese Flounder ◽  
Type Ii ◽  
Linkage Groups

AbstractA genetic linkage map of Japanese flounder was constructed using 165 doubled haploids (DHs) derived from a single female. A total of 574 genomic microsatellites (type II SSRs) and expressed sequence tag (EST)-derived markers (EST-SSRs) were mapped to 24 linkage groups. The length of linkage map was estimated as 1270.9 centiMorgans (cM), with an average distance between markers of 2.2 cM. The EST-SSRs were used together with type II SSR markers to construct the Japanese flounder genetic linkage map which will facilitate identify quantitative trait locus (QTL) controlling important economic traits in Japanese flounder. Thus, twelve skeletal traits at 2 years of age were measured for all DHs. Forty-one QTLs were detected on 14 linkage groups and totally account for a small proportion of phenotypic variation (4.5 to 17.3%). Most of QTLs detected distribute on linkage groups 5 (9 QTLs), 8 (9 QTLs), 9 (5 QTLs) and 20 (4 QTLs), in which, some QTLs perform the pleiotropy.

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.

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.

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