Large disparity in recombination fractions reported in Picea mariana for the Aat-1/Pgi-2 linkage group

1990 ◽  
Vol 68 (3) ◽  
pp. 518-520 ◽  
Author(s):  
Gordon S. Ringius ◽  
David J. Innes
Keyword(s):  
Linkage Group ◽  
Natural Population ◽  
Picea Mariana ◽  
Segregation Analysis ◽  
Recombination Fraction ◽  
Linkage Groups ◽  
Substantial Variation ◽  
Eastern Canada ◽  
Locus Pair ◽  
Temporal And Spatial

A survey of 84 trees in a natural population of Picea mariana located near St. John's, Newfoundland, yielded 3 trees heterozygous for the Aat-1/Pgi-2 linked locus pair. Segregation analysis of this linkage group in 330 megagametophytes resulted in an estimated pooled recombination fraction of 0.015. This is the lowest known recombination fraction for this linkage group in the Pinaceae. It is in contrast with earlier reports of recombination fractions of 0.155 and 0.250 from other populations of P. mariana in eastern Canada. The presence of substantial variation in recombination fractions in populations from eastern Canada precludes a regional selection–adaptation explanation. The cause of this variation is unknown. Substantial variation, both temporal and spatial, in other linkage groups suggests that the basis of linkage variation is complex and in need of further investigation in the Pinaceae.

Linkage group XIX of Chlamydomonas reinhardtii has a linear map.

Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher
Keyword(s):  
Linkage Group ◽  
Chlamydomonas Reinhardtii ◽  
Mutant Strain ◽  
Meiotic Recombination ◽  
Temperature Sensitive ◽  
Unusual Property ◽  
Linkage Groups ◽  
Excess Number ◽  
Chiasma Interference ◽  
Double Crossovers

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.

Identification of RAPD markers linked to common bacterial blight resistance genes in Phaseolus vulgaris L.

Genome ◽  
1997 ◽  
Vol 40 (4) ◽  
pp. 544-551 ◽  
Author(s):  
Yonghe Bai ◽  
T. E. Michaels ◽  
K. P. Pauls
Keyword(s):  
Phaseolus Vulgaris ◽  
Linkage Group ◽  
Bacterial Blight ◽  
Rapd Markers ◽  
Interspecific Cross ◽  
Breeding Population ◽  
Common Bacterial Blight ◽  
Linkage Groups ◽  
Phaseolus Vulgaris L ◽  
Total Contribution

Seven hundred and fifty-six random primers were screened with bulks of genomic DNA from common bacterial blight (CBB) resistant and susceptible bean plants. The plants were from a breeding population derived from an interspecific cross between Phaseolus acutifolius and Phaseolus vulgaris. Four RAPD markers, named R7313, RE416, RE49, and R4865, were found to be significantly associated with CBB resistance in this population. Forty-nine molecular markers segregating in the population were clustered into 8 linkage groups by a MAPMAKER linkage analysis. The largest linkage group was 140 cM long and contained 25 marker loci, including marker R4865. Markers R7313, RE416, and RE49 were clustered on another linkage group. A regression analysis indicated that the markers in these two groups together accounted for 81% of the variation in CBB resistance in the population. The addition of another marker, M56810, which was not individually associated with CBB resistance, increased the total contribution to the trait to 87%.Key words: Phaseolus vulgaris L., common bacterial blight (CBB), polymerase chain reaction (PCR), RAPD markers, linkage groups.

The "reindeer" mutation and a revision of linkage groups V and X in the flour beetle, Tribolium castaneum

1984 ◽  
Vol 26 (6) ◽  
pp. 762-764 ◽  
Author(s):  
Peter S. Dawson
Keyword(s):  
Linkage Group ◽  
Key Words ◽  
Tribolium Castaneum ◽  
Linkage Groups ◽  
Dominant Mutation ◽  
Genetic Studies ◽  
Group V ◽  
Flour Beetle ◽  
Dominant Mutants

Reindeer (Rd) is a dominant mutation affecting antenna morphology in the tenebrionid flour beetle, Tribolium castaneum. In contrast with most dominant mutants previously described for this species, homozygotes are fully viable, thus making Rd very useful for genetic studies. Rd is tentatively assigned to either linkage group IX or X. Abbreviated appendages (aa), formerly placed in linkage group X, is reassigned to linkage group V on the basis of demonstrated linkage to jet (j).Key words: Tribolium, mutation Rd, linkage, antenna morphology.

scholarly journals GENETICS OF ISOZYMES AND ANALYSIS OF ISOZYMES LINKAGE AND MORPHOLOGICAL LOCI IN SUNFLOWER (Helianthus annuus L.) / GENETICA DE ISOFERMENTOS Y EL ACOMPLAMIENTO DE LÓCUSES MORFOLOGICOS E ISOFERMENTICOS EN GIRASOL / GENETIQUE DES ISOFERMENTS ET LIAISON DES LOCUS MORPHOLOGIQUES ET CEUX-CI D’ISOFERMENTS AU TOURNESOL

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 65-76
Author(s):  
V.V. Kirichenko ◽  
V.N. Popov
Keyword(s):  
Acid Phosphatase ◽  
Linkage Group ◽  
Helianthus Annuus ◽  
Malate Dehydrogenase ◽  
Morphological Traits ◽  
Fertility Restoration ◽  
Linkage Groups ◽  
Esterase Loci ◽  
Mature Seeds ◽  
Male Fertility Restoration

SUMMARY The genetics of anodal esterase (Est), cathodal esterase (cEst), cathodal acid phosphatase (cAcp) and malate dehydrogenase (Mdh) has been studied in mature seeds and leaves (genetics of cAcp and Mdh has not been studied in leaves) of sunflower (Helianthus annuus L.). A total of ten loci (four loci of anodal esterase, two loci of cathodal esterase, three loci of malate dehydrogenase and one locus of cathodal acid phosphatase) have been identified and described. Five esterase loci (Est1, Est2, Est3, Est4, cEst5), three malate dehydrogenase loci and one locus of cathodal acid phosphatase are expressed in seeds. Three esterase loci (Est2, cEst5 and cEst6) are expressed in leaves. The analysis of linkage between these loci has been made. Two linkage groups have been found. The sequence of the loci in the first linkage group was Mdh2-Est1- Est2-Est3-cEst5. In the second linkage group it was Est4-cAcp1. Linkages have been analyzed between three isoenzymatic loci expressed in leaves and between two loci controlling morphological traits (branched stem and male fertility restoration). The linkage between morphological traits and isoenzymatic loci has not been revealed. It has been revealed in Br-Rf pair.

scholarly journals QTL Across Fruit Development in Red Raspberry, A Study of A Primocane X Biennial Raspberry Population.

2021 ◽  
Author(s):  
Julie Graham ◽  
Kay Smith ◽  
Katrin MacKenzie ◽  
Linda Milne ◽  
Nikki Jennings ◽  
...  
Keyword(s):  
Linkage Group ◽  
Genetic Control ◽  
Fruit Ripening ◽  
Fruit Development ◽  
Developmental Stages ◽  
Developmental Process ◽  
Linkage Groups ◽  
Red Raspberry ◽  
Ripening Process ◽  
Second Year

Abstract Background The changing climate is altering timing of key fruit ripening processes and increasing the occurrence of fruit defects. This work aimed to expand our knowledge of the genetic control of the ripening process in raspberry by examining a biennial x primocane F1 population to determine if the progeny exhibited both primocane and biennial flowering modes, which if any was dominant, and to identify QTL and genome locations associated with fruit development to understand how developmental control in this population differs from a biennial x biennial F1 population previously studied. Results The progeny from this biennial x primocane population exhibited primocane fruiting completing their lifecycle in a single season and also fruiting on second-year wood not removed in season one. QTL associated with rate of fruit development were identified on both primocane and fruiting canes with both parents impacting. Conclusions Novel QTL associated with the developmental process of primocane fruiting were identified. These in the main, differed from developmental QTL for similar developmental stages on fruiting canes (second year canes) with only one significant overlap on linkage group 6. In general, the process of development on fruiting canes overall differed from that in a biennial x biennial population, with the differences being greatest on linkage groups 3 and 6 suggesting control of development differs in the different fruiting types. Further understanding will be achieved by examining genome regions linked to QTL to allow breeding to meet climate requirements for yield stability.

scholarly journals Centromere-Linkage Analysis and Consolidation of the Zebrafish Genetic Map

Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1277-1288
Author(s):  
Stephen L Johnson ◽  
Michael A Gates ◽  
Michele Johnson ◽  
William S Talbot ◽  
Sally Horne ◽  
...  
Keyword(s):  
Linkage Group ◽  
Linkage Analysis ◽  
Genetic Analysis ◽  
Linkage Map ◽  
Rapid Method ◽  
Genetic Map ◽  
Dna Polymorphisms ◽  
Linkage Groups

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.

motA1552, a mutation of Dictyostelium discoideum having pleiotropic effects on motility and discoidin I regulation.

Genetics ◽  
1988 ◽  
Vol 118 (3) ◽  
pp. 425-436
Author(s):  
S C Kayman ◽  
R Birchman ◽  
M Clarke
Keyword(s):  
Linkage Group ◽  
Dictyostelium Discoideum ◽  
Growth Temperature ◽  
Segregation Analysis ◽  
Pleiotropic Effects ◽  
Temperature Sensitive ◽  
Temperature Induction ◽  
Group Ii ◽  
Unstable Mutations ◽  
Axenic Growth

Abstract The Dictyostelium discoideum mutant MC2 exhibits temperature-sensitive growth, temperature-sensitive motility, and temperature induction of discoidin I synthesis. These three phenotypes of MC2 were not separated in the genetic experiments reported here. They were therefore assigned to the mutation motA1552, which was mapped to linkage group II by segregation analysis and by analysis of mitotic recombinant diploids. In one motA1552 strain, loss of motility preceded accumulation of discoidin I by 3 hr, indicating that discoidin I is not involved in generation of the motility defect. Expression of motA1552 phenotypes varied both among strains carrying the mutation, and among different clones of a particular strain. MC2 and its derivatives displayed elevated levels of recombination between whiA and acrA on linkage group II, and yielded highly unstable mutations at the acrA locus. Accumulation of large amounts of discoidin I during axenic growth of strain AX3 was found to depend on the presence of a second linkage group II mutation, daxA1551. This mutation was already present in the strain mutagenized to isolate motA1552, complicating explication of motA1552 action.

A new gene for resistance to Dysaphis pyri in pear and identification of flanking microsatellite markers

Genome ◽  
2008 ◽  
Vol 51 (12) ◽  
pp. 1026-1031 ◽  
Author(s):  
Kate M. Evans ◽  
Ceri L. Govan ◽  
Felicidad Fernández-Fernández
Keyword(s):  
Linkage Group ◽  
Microsatellite Markers ◽  
Major Gene ◽  
Pyrus Communis ◽  
Linkage Groups ◽  
European Pear ◽  
New Gene

Dysaphis pyri is an important aphid pest of European pear ( Pyrus communis ) cultivars, none of which are currently reported to be resistant. In this study, we produced a progeny of the European pear Comice crossed with an accession of snow pear (Pyrus nivalis) that segregated for resistance to D. pyri in a Mendelian fashion, indicating the presence of a major gene, Dp-1. Following screening of the parents and seedlings with microsatellite markers, cosegregation analysis indicated that Dp-1 is flanked by NH006b and NH014a on linkage group 17, 2.3 and 3.6 cM away, respectively. Evidence is also presented for the duplication of linkage groups 9 and 17, which is a consequence of the allopolyploid origin of pear.

scholarly journals Genetic studies on flagellum mutants of Chlamydomonas reinhardii

1972 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Anne McVittie
Keyword(s):  
Linkage Group ◽  
Wild Type ◽  
Linkage Groups ◽  
Genetic Studies ◽  
Chlamydomonas Reinhardii ◽  
The Third ◽  
Group Ii

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.

A high-density genetic linkage map of a black spruce (Picea mariana) × red spruce (Picea rubens) interspecific hybrid

Genome ◽  
2011 ◽  
Vol 54 (2) ◽  
pp. 128-143 ◽  
Author(s):  
Bum-Yong Kang ◽  
John E. Major ◽  
Om P. Rajora
Keyword(s):  
Picea Mariana ◽  
Interspecific Hybrid ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Black Spruce ◽  
Picea Rubens ◽  
Red Spruce ◽  
Linkage Groups ◽  
Genomic Resource ◽  
Map Distance

Genetic maps provide an important genomic resource of basic and applied significance. Spruce ( Picea ) has a very large genome size (between 0.85 × 1010 and 2.4 × 1010 bp; 8.5–24.0 pg/1C, a mean of 17.7 pg/1C ). We have constructed a near-saturated genetic linkage map for an interspecific backcross (BC1) hybrid of black spruce (BS; Picea mariana (Mill.) B.S.P.) and red spruce (RS; Picea rubens Sarg.), using selectively amplified microsatellite polymorphic loci (SAMPL) markers. A total of 2284 SAMPL markers were resolved using 31 SAMPL–MseI selective nucleotide primer combinations. Of these, 1216 SAMPL markers showing Mendelian segregation were mapped, whereas 1068 (46.8%) SAMPL fragments showed segregation distortion at α = 0.05. Maternal, paternal, and consensus maps consistently coalesced into 12 linkage groups, corresponding to the haploid chromosome number (1n = 1x = 12) of 12 in the genus Picea. The maternal BS map consisted of 814 markers distributed over 12 linkage groups, covering 1670 cM, with a mean map distance of 2.1 cM between adjacent markers. The paternal BS × RS map consisted of 773 markers distributed over 12 linkage groups, covering 1563 cM, with a mean map distance of 2.0 cM between adjacent markers. The consensus interspecific hybrid BC1 map consisted of 1216 markers distributed over 12 linkage groups, covering 1865 cM (98% genome coverage), with a mean map distance of 1.5 cM between adjacent markers. The genetic map reported here provides an important genomic resource in Picea, Pinaceae, and conifers.

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