Identification and Genetic Analysis of a Novel Allelic Variation of Brittle-1 with
Endosperm Mutant in Maize

Genetic variation in cucumber accessions from China was assessed by examining variation at 21 polymorphic isozyme loci. Principal component analysis of allelic variation allowed for the depiction of two distinct groupings of Chinese accessions collected in 1994 and 1996 (67 accessions). Six isozyme loci (Gpi, Gr, Mdh-2, Mpi-2, Pep-gl, and Pep-la) were important in elucidating these major groups. These groupings were different from a single grouping of Chinese 146 accessions acquired before 1994. Allelic variation in Chinese accessions allowed for comparisons with other accessions in the U.S. National Plant Germplasm System (U.S. NPGS) collection grouped by continent and sub-continent. When Chinese accessions taken collectively were compared with an array of 853 C. sativus U.S. NPGS accessions examined previously, relationships differed between accessions grouped by country or subcontinent. Data indicate that acquisition of additional Chinese and Indian cucumber accessions would be strategically important for increasing genetic diversity in the U.S. NPGS cucumber collection.

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Diversity Outbred Mice at 21: Maintaining Allelic Variation in the Face of Selection

G3 Genes|Genome|Genetics ◽

10.1534/g3.116.035527 ◽

2016 ◽

Vol 6 (12) ◽

pp. 3893-3902 ◽

Cited By ~ 38

Author(s):

Elissa J Chesler ◽

Daniel M Gatti ◽

Andrew P Morgan ◽

Marge Strobel ◽

Laura Trepanier ◽

...

Keyword(s):

Genetic Analysis ◽

Sex Chromosome ◽

Allelic Variation ◽

Allele Frequencies ◽

Transmission Ratio Distortion ◽

Chromosome 2 ◽

Effective Population ◽

Mouse Population ◽

Diversity Outbred ◽

The Impact

Abstract Multi-parent populations (MPPs) capture and maintain the genetic diversity from multiple inbred founder strains to provide a resource for high-resolution genetic mapping through the accumulation of recombination events over many generations. Breeding designs that maintain a large effective population size with randomized assignment of breeders at each generation can minimize the impact of selection, inbreeding, and genetic drift on allele frequencies. Small deviations from expected allele frequencies will have little effect on the power and precision of genetic analysis, but a major distortion could result in reduced power and loss of important functional alleles. We detected strong transmission ratio distortion in the Diversity Outbred (DO) mouse population on chromosome 2, caused by meiotic drive favoring transmission of the WSB/EiJ allele at the R2d2 locus. The distorted region harbors thousands of polymorphisms derived from the seven non-WSB founder strains and many of these would be lost if the sweep was allowed to continue. To ensure the utility of the DO population to study genetic variation on chromosome 2, we performed an artificial selection against WSB/EiJ alleles at the R2d2 locus. Here, we report that we have purged the WSB/EiJ allele from the drive locus while preserving WSB/EiJ alleles in the flanking regions. We observed minimal disruption to allele frequencies across the rest of the autosomal genome. However, there was a shift in haplotype frequencies of the mitochondrial genome and an increase in the rate of an unusual sex chromosome aneuploidy. The DO population has been restored to genome-wide utility for genetic analysis, but our experience underscores that vigilant monitoring of similar genetic resource populations is needed to ensure their long-term utility.

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Allelic variation of Mhc class II in Atlantic salmon; a population genetic analysis

Heredity ◽

10.1046/j.1365-2540.1998.00321.x ◽

1998 ◽

Vol 80 (5) ◽

pp. 568-575 ◽

Cited By ~ 19

Author(s):

Åsa Langefors ◽

Torbjörn Von Schantz ◽

Bengt Widegren

Keyword(s):

Genetic Analysis ◽

Atlantic Salmon ◽

Mhc Class Ii ◽

Population Genetic ◽

Allelic Variation ◽

Class Ii ◽

Population Genetic Analysis

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ASSESSMENT OF VARIABILITY WITHIN ELECTROMORPHS OF ALCOHOL DEHYDROGENASE IN DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/95.2.467 ◽

1980 ◽

Vol 95 (2) ◽

pp. 467-475

Author(s):

Martin Kreitman

Keyword(s):

Drosophila Melanogaster ◽

Genetic Analysis ◽

Alcohol Dehydrogenase ◽

Natural Population ◽

Allelic Variation ◽

Structural Locus ◽

Standard Methods ◽

Electrophoretic Mobilities ◽

Allelic Variability ◽

Allelic Differences

ABSTRACT Ninety-six isochromosomal lines of Drosophila melanogaster from a natural population were screened electrophoretically for unusual mobility variants at the alcohol dehydrogenase locus, using a total of eight conditions of acrylamide electrophoresis. No additional mobility variation was found among the 50 "slow" and 46 "fast" mobility lines beyond that detected by standard methods of electrophoresis. However, two thermostability variants recovered by R. MILKMAN from a natural population, whose electrophoretic mobilities were previously thought to be indistinguishable from those of "standard" alleles, are distinguishable from the standard elcctromorphs by these procedures. These results suggest that the Adhlocus, although polymorphic, does not harbor substantial amounts of "hidden" allelic variability. This study also reports the appearance of substantial mobility variation among isogenic lines that can be induced under specific conditions of sample preparation involving the pretreatment of samples with NAD and acetone. However, genetic analysis demonstrates that this variability cannot be attributed to allelic differences at the structural locus, but instead appears to be dependent upon the concentration of the enzyme in a sample. These results are discussed in relation to the distribution of allelic variation at other enzyme loci.

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Identification and cross-validation of genetic loci conferring resistance to Septoria nodorum blotch using a German multi-founder winter wheat population

Theoretical and Applied Genetics ◽

10.1007/s00122-020-03686-x ◽

2020 ◽

Author(s):

Min Lin ◽

Melanie Stadlmeier ◽

Volker Mohler ◽

Kar-Chun Tan ◽

Andrea Ficke ◽

...

Keyword(s):

Genetic Analysis ◽

Quantitative Trait ◽

Marker Assisted Selection ◽

Allelic Variation ◽

Minor Effect ◽

Septoria Nodorum ◽

Additive Effects ◽

Resistance Qtl ◽

Septoria Nodorum Blotch ◽

Magic Population

Abstract Key message We identified allelic variation at two major loci, QSnb.nmbu-2A.1 and QSnb.nmbu-5A.1, showing consistent and additive effects on SNB field resistance. Validation of QSnb.nmbu-2A.1 across genetic backgrounds further highlights its usefulness for marker-assisted selection. Abstract Septoria nodorum blotch (SNB) is a disease of wheat (Triticum aestivum and T. durum) caused by the necrotrophic fungal pathogen Parastagonospora nodorum. SNB resistance is a typical quantitative trait, controlled by multiple quantitative trait loci (QTL) of minor effect. To achieve increased plant resistance, selection for resistance alleles and/or selection against susceptibility alleles must be undertaken. Here, we performed genetic analysis of SNB resistance using an eight-founder German Multiparent Advanced Generation Inter-Cross (MAGIC) population, termed BMWpop. Field trials and greenhouse testing were conducted over three seasons in Norway, with genetic analysis identifying ten SNB resistance QTL. Of these, two QTL were identified over two seasons: QSnb.nmbu-2A.1 on chromosome 2A and QSnb.nmbu-5A.1 on chromosome 5A. The chromosome 2A BMWpop QTL co-located with a robust SNB resistance QTL recently identified in an independent eight-founder MAGIC population constructed using varieties released in the United Kingdom (UK). The validation of this SNB resistance QTL in two independent multi-founder mapping populations, regardless of the differences in genetic background and agricultural environment, highlights the value of this locus in SNB resistance breeding. The second robust QTL identified in the BMWpop, QSnb.nmbu-5A.1, was not identified in the UK MAGIC population. Combining resistance alleles at both loci resulted in additive effects on SNB resistance. Therefore, using marker assisted selection to combine resistance alleles is a promising strategy for improving SNB resistance in wheat breeding. Indeed, the multi-locus haplotypes determined in this study provide markers for efficient tracking of these beneficial alleles in future wheat genetics and breeding activities.

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