Duplicate Loci as QTL

Crop Science ◽  
2002 ◽  
Vol 42 (5) ◽  
pp. 1679-1687 ◽  
Author(s):  
Stephen J. Szalma ◽  
Maurice E. Snook ◽  
Bradley S. Bushman ◽  
Katherine E. Houchins ◽  
Michael D. McMullen
Keyword(s):  
Duplicate Loci

Probability of Fixation of Nonfunctional Genes at Duplicate Loci

1973 ◽  
Vol 107 (955) ◽  
pp. 362-372 ◽  
Author(s):  
Masatoshi Nei ◽  
Arun K. Roychoudhury
Keyword(s):  
Duplicate Loci ◽  
Probability Of Fixation

Patterns of genome duplication within the Brassica napus genome

Genome ◽  
2003 ◽  
Vol 46 (2) ◽  
pp. 291-303 ◽  
Author(s):  
I A.P Parkin ◽  
A G Sharpe ◽  
D J Lydiate
Keyword(s):  
Brassica Napus ◽  
Genome Duplication ◽  
Chromosomal Rearrangements ◽  
Centric Fusion ◽  
Linkage Groups ◽  
Gross Chromosomal Rearrangements ◽  
A Genome ◽  
C Genome ◽  
Homologous Locus ◽  
Duplicate Loci

The progenitor diploid genomes (A and C) of the amphidiploid Brassica napus are extensively duplicated with 73% of genomic clones detecting two or more duplicate sequences within each of the diploid genomes. This comprehensive duplication of loci is to be expected in a species that has evolved through a polyploid ancestor. The majority of the duplicate loci within each of the diploid genomes were found in distinct linkage groups as collinear blocks of linked loci, some of which had undergone a variety of rearrangements subsequent to duplication, including inversions and translocations. A number of identical rearrangements were observed in the two diploid genomes, suggesting they had occurred before the divergence of the two species. A number of linkage groups displayed an organization consistent with centric fusion and (or) fission, suggesting this mechanism may have played a role in the evolution of Brassica genomes. For almost every genetically mapped locus detected in the A genome a homologous locus was found in the C genome; the collinear arrangement of these homologous markers allowed the primary regions of homoeology between the two genomes to be identified. At least 16 gross chromosomal rearrangements differentiated the two diploid genomes during their divergence from a common ancestor.Key words: genome evolution, Brassicaeae, polyploidy, homoeologous linkage groups.

The 93D heat shock locus of Drosophila melanogaster: modulation by genetic and developmental factors

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 677-683 ◽  
Author(s):  
S. C. Lakhotia
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Developmental Regulation ◽  
Sequence Divergence ◽  
Unique Region ◽  
Reading Frame ◽  
Beta Alanine ◽  
Functional Conservation ◽  
Duplicate Loci ◽  
93D Locus

The 93D locus in Drosophila melanogaster and the 93D-like loci in other species of Drosophila, collectively termed hsr ω (heat shock RNA omega) locus, display several unique and intriguing features: (i) developmental regulation and selective induction by several agents like benzamide, colchicine, thiamphenicol, vit-B6; (ii) functional conservation in the genus but a very rapid DNA base sequence divergence; (iii) in spite of the rapid DNA sequence divergence, a strong conservation of organization (a 5′ unique region and a 3′ long tandem repeat region) and the pattern of multiple ω transcripts in the genus; (iv) a general nontranslatability of all the three major species of ω transcripts (an ~ 10-kb ω1, a 2.0-kb ω2, and a 1.2-kb ω3 species) although some recent evidence favours translatability of a small open reading frame (~ 23 – 27 amino acid long) in the ω3 transcript; (v) dispensability of the hsr ω locus for heat shock protein synthesis but indispensability for viability of flies. The heat shock inducibility of the 93D locus of D. melanogaster is selectively repressed by (i) combination of heat shock with another inducer of 93D; (ii) rearing of larvae at 10 °C; (iii) heterozygous deficiency for the 93D region; and (iv) conditions that alter levels of beta-alanine. In all cases of repression of the 93D locus during heat shock, the 87A and 87C loci (the two duplicate loci harbouring multiple copies for hsp70 and the alpha–beta repeat sequences (at 87C)) develop unequal puffs. The hsr ω locus appears to be under a complex system of regulation involving autoregulation as well as regulation by other factors in the cell which possibly operate through different control elements on the locus.Key words: benzamide, colchicine, beta-alanine, hsr ω, heat shock puffs, Drosophila.

An esterase duplication in Drosophila: Differences in expression of duplicate loci within and among related species

1982 ◽  
Vol 20 (9-10) ◽  
pp. 929-942 ◽  
Author(s):  
E. Zouros ◽  
W. van Delden ◽  
R. Odense ◽  
H. van Dijk
Keyword(s):  
Related Species ◽  
Duplicate Loci

scholarly journals JOINT SEGREGATION OF BIOCHEMICAL LOCI IN SALMONIDAE. II. LINKAGE ASSOCIATIONS FROM A HYBRIDIZED SALVELINUS GENOME (S. NAMAYCUSH x S. FONTINALIS)

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 707-726
Author(s):  
Bernie May ◽  
Mark Stoneking ◽  
James E Wright
Keyword(s):  
Brook Trout ◽  
Lake Trout ◽  
Salvelinus Fontinalis ◽  
De Novo ◽  
Homeologous Chromosome ◽  
Homeologous Chromosomes ◽  
Joint Segregation ◽  
Duplicate Loci ◽  
Haploid Complement

ABSTRACT The results of more than 300 parwise examinations of biochemical loci for joint segregation in brook trout (Salvelinus fontinalis) and in the hybridized genome of lake trout (S. namaycush) × brook trout are summarized. Nineteen loci have been assigned to the following eight linkage groupings on the basis of nonrandom assortment, including cases of both classical linkage and pseudolinkage: ODH with PMI with PGI-3, PGI-2 with SDH, ADA-1 with AGP-2, AAT-(1,2) with AGP-1 with MDH-I, MDH-3 with MDH-4, LDH-3 with LDH-4, IDH-3 with ME-2 and GUS with CPK-I. Pseudolinkage (an excess of nonparental progeny types) was observed only for male testcross parents. The results suggest that this phenomenon involves homeologous chromosome arms as evidenced by the de novo association of presumed duplicate loci in each case. Classical linkage has not been found for the five pairs of duplicate loci examined in Salvelinus, suggesting that not all of the eight metacentrics in the haploid complement involve fusions of homeologous chromosomes. Females consistently showed a greater degree of recombination.

scholarly journals RATE OF GENE SILENCING AT DUPLICATE LOCI: A THEORETICAL STUDY AND INTERPRETATION OF DATA FROM TETRAPLOID FISHES

Genetics ◽  
1980 ◽  
Vol 95 (1) ◽  
pp. 237-258 ◽  
Author(s):  
Wen-Hsiung Li
Keyword(s):  
Large Scale ◽  
Null Allele ◽  
Gene Loss ◽  
Extinction Time ◽  
Effective Population ◽  
Tight Linkage ◽  
Order Of Magnitude ◽  
The Mean ◽  
Duplicate Loci ◽  
Sheltering Effect

ABSTRACT A large-scale simulation has been conducted on the rate of gene loss at duplicate loci under irreversible mutation. It is found that tight linkage does not provide a strong sheltering effect, as thought by previous authors; indeed, the mean loss time for the case of tight linkage is of the same order of magnitude as that for no linkage, as long as Nu is not much larger than 1, where N is the effective population size and u the mutation rate. When Nu is 0.01 or less, the two loci behave almost as neutral loci, regardless of linkage, and the mean loss time is about only half the mean extinction time for a neutral allele under irreversible mutation. However, the former becomes two or more times larger than the latter when Nu ≥ 1.—In the simulation, the sojourn times in the frequency intervals (0, 001) and (0.99, 1) and the time for the frequency of the null allele to reach 0.99 at one of the two loci have also been recorded. The results show that the populatian is monomorphic for the normal allele most of the time if Nu ≤ 0.01, but polymorphic for the null and the normal alleles most of the time if Nu ≥ 0.1.—The distribution of the frequency of the null allele in an equilibrium tetraploid population has been studied analytically. The present results have been applied to interpret data from some fish groups that are of tetraploid origin, and a model for explaining the slow rate of gene loss in these fishes is proposed.

scholarly journals Protein variation and duplicate loci in the Atlantic salmon, Salmo solar L.

1980 ◽  
Vol 36 (2) ◽  
pp. 147-165 ◽  
Author(s):  
T. F. Cross ◽  
R. D. Ward
Keyword(s):  
Genetic Variation ◽  
Gene Duplication ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmonid Fishes ◽  
Protein Variation ◽  
Stock Discrimination ◽  
General Variation ◽  
The Mean ◽  
Duplicate Loci

SUMMARYA natural population of Atlantic salmon, Salmo salar L. was screened for genetic variation at 59 protein loci, using a sample of parr, the juvenile freshwater stage. The mean heterozygosity per locus, estimated at 0·033 ± 0·014, is similar to that described in other salmonid species but low for fish species in general. Variation was observed at AAT, IDH, MD–ME, GLO, ADA, and SDH loci. The methods described should prove useful in stock discrimination and in producing salmon for restocking and sea-rearing. The observed extent of gene duplication is discussed in relation to the evolution and systematics of the salmonid fishes.

scholarly journals GENETIC ANALYSIS OF DUPLICATE MALATE DEHYDROGENASE LOCI IN THE PINK SALMON, ONCORHYNCHUS GORBUSCHA

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 65-72
Author(s):  
Nevin Aspinwall
Keyword(s):  
Genetic Analysis ◽  
Malate Dehydrogenase ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Limited Evidence ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
A Subunit ◽  
B Subunits ◽  
Duplicate Loci

ABSTRACT The results of breeding experiments with the pink salmon, Oncorhynchus gorbuscha, indicate that s-MDH-A and s-MDH-B subunits are each encoded by duplicate loci. Limited evidence suggests also that the two loci encoding for the s-MDH-A subunit are each polymorphic and linked or pseudolinked.

Linkage relationships of 19 allozyme encoding loci within the commercial mushroom genus Pleurotus

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 888-895 ◽  
Author(s):  
Bernie May ◽  
Kathrine J. Henley ◽  
Christine G. Fisher ◽  
Daniel J. Royse
Keyword(s):  
Linkage Map ◽  
Interspecific Hybrids ◽  
Single Locus ◽  
Linkage Groups ◽  
Edible Fungi ◽  
Single Spore ◽  
Joint Segregation ◽  
The Individual ◽  
Duplicate Loci ◽  
Linkage Relationships

Single spore derived Pleurotus spp. isolates from four commercial lines (two P. sapidus, one P. florida, and one P. ostreatus) and from two interspecific hybrids (P. sajor-caju × P. sapidus) were analyzed for single locus and joint segregation of 25 allozyme encoding loci. The two alleles at the individual loci departed significantly in their segregation from a 1:1 Mendelian ratio in 26% of the intraspecific and 29% of the interspecific tests. Six linkage groups were identified as follows: Dia-1 ~ Est-5; Tpi ~ Pgd-2 ~ Skdh; (Fum) ~ Pgm-2 ~ Pgd-1 ~ PepLgg-1 ~ Gr-2; Ndh ~ Gr-1; Np ~ PepGl-1 ~ Aat-2 ~ Pgk ~ Mup; and Gr-4 ~ Mdh-1. The duplicate loci coding for GR, PEP-LGG, PGM, and PGD were both not linked to each other and not part of duplicate linkage groups. Six loci were not shown to be linked to any other loci (Lap, Pgm-1, Ha, Gpi, PepPap, and PepLgg-2), although the latter two loci were only tested against four and five loci, respectively. The first linkage map of 19 allozyme encoding loci for the Pleurotus genome is presented.Key words: Pleurotus, allozymes, linkage map, inheritance, edible fungi.

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