scholarly journals Signatures of Dobzhansky-Muller Incompatibilities in the Genomes of Recombinant Inbred Lines

2015 ◽  
Author(s):  
Maria Colomé-Tatché ◽  
Frank Johannes
Keyword(s):  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Develop Model ◽  
Selection Signatures ◽  
In The Wild ◽  
Lower Fertility ◽  
Viable Seeds ◽  
Genomic Regions ◽  
Theoretical Results

In the construction of Recombinant Inbred Lines (RILs) from two divergent inbred parents certain genotype (or epigenotype) combinations may be functionally "incompatible" when brought together in the genomes of the progeny, thus resulting in sterility or lower fertility. Natural selection against these epistatic combinations during inbreeding can change haplotype frequencies and distort linkage disequilibrium (LD) relations between loci within and across chromosomes. These LD distortions have received increased experimental attention, because they point to genomic regions that may drive Dobzhansky-Muller-type of reproductive isolation and, ultimately, speciation in the wild. Here we study the selection signatures of two-locus epistatic incompatibility models and quantify their impact on the genetic composition of the genomes of 2-way RILs obtained by selfing. We also consider the biases introduced by breeders when trying to counteract the loss of lines by selectively propagating only viable seeds. Building on our theoretical results, we develop model-based maximum likelihood (ML) tests which can be employed in pairwise genome scans for incompatibility loci using multi-locus genotype data. We illustrate this ML approach in the context of two published A. thaliana RIL panels. Our work lays the theoretical foundation for studying more complex systems such as RILs obtained by sibling mating and/or from multi-parental crosses.

scholarly journals Molecular mapping of QTLs for resistance to early and late Fusarium wilt in chickpea

2014 ◽  
Vol 50 (No. 2) ◽  
pp. 171-176 ◽  
Author(s):  
B.S. Patil ◽  
R.L. Ravikumar ◽  
J.S. Bhat ◽  
C.D. Soregaon
Keyword(s):  
Fusarium Wilt ◽  
Recombinant Inbred ◽  
Molecular Mapping ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Reference Map ◽  
Genomic Regions ◽  
Marker Distance

A molecular map of chickpea was constructed using F<sub>9</sub>:F<sub>10</sub> recombinant inbred lines from an intraspecific cross between Fusarium wilt susceptible (JG 62) and resistant (WR 315) genotypes. A total of 23 markers with LOD scores of &gt; 3.0 were mapped on the recombinant inbred lines (RILs). Twenty sequence tagged microsatellites (STMSs) and three amplified fragment length polymorphisms (AFLPs) covered 300.2 cM in five linkage groups at an average inter-marker distance of 13 cM. Early and late wilting due to Fusarium infection was recorded in RILs at 30&nbsp;and 60 DAS, respectively. There was a significant variation among RILs for wilt resistance for both early and late wilting. QTLs associated with early (30 days after sowing (DAS)) and late (60&nbsp;DAS) wilting are located on LG II. The flanking markers for these QTLs were the same as those of previous reports. Five STMS markers located on LG II of reference map (interspecific) were mapped on LG II of the present map (intraspecific) with minor changes in the order of markers indicating the conservation of these genomic regions across the Cicer species.

scholarly journals QTL analysis of novel genomic regions associated with yield and yield related traits in new plant type based recombinant inbred lines of rice (Oryza sativa L.)

2012 ◽  
Vol 12 (1) ◽  
pp. 137 ◽  
Author(s):  
Balram Marathi ◽  
Smriti Guleria ◽  
Trilochan Mohapatra ◽  
Rajender Parsad ◽  
Nagarajan Mariappan ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Qtl Analysis ◽  
Recombinant Inbred ◽  
Oryza Sativa L ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Plant Type ◽  
Genomic Regions

Development of a set of near isogenic and backcross recombinant inbred lines containing most of the Lycopersicon hirsutum genome in a L. esculentum genetic background: A tool for gene mapping and gene discovery

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 803-813 ◽  
Author(s):  
Antonio J Monforte ◽  
Steve D Tanksley
Keyword(s):  
Genetic Resources ◽  
Recombinant Inbred ◽  
Genetic Background ◽  
Recombinant Inbred Lines ◽  
Pollen Viability ◽  
Inbred Lines ◽  
Allelic Frequency ◽  
Isogenic Line ◽  
Genomic Regions ◽  
Backcross Recombinant Inbred Lines

A novel population consisted of a set of 99 near isogenic lines (NILs) and backcross recombinant inbred lines (BCRILs) derived from a cross between the cultivated tomato Lycopersicon esculentum cv. E6206 and L. hirsutum accession LA1777 is presented. Most of the lines contain a single defined introgression from L. hirsutum in the L. esculentum genetic background and together, the lines provide a coverage of more than the 85% of the L. hirsutum genome. These lines represent a new tool to uncover the genetic resources hidden in L. hirsutum as well as to study the genes responsible of its unique biology. Furthermore, the study of the allelic frequency and heterozygosity among BCRILs showed that specific genomic regions were likely subjected to unintentional selection pressures during the stock development. Genes involved in the reproductive behavior and (or) pollen viability are hypothesized to be responsible for these alterations.Key words: germplasm, near isogenic line, tomato, genetic resources.

scholarly journals Tightly-linked antagonistic-effect loci underlie polygenic demographic variation in C. elegans

2018 ◽  
Author(s):  
Max R. Bernstein ◽  
Stefan Zdraljevic ◽  
Erik C. Andersen ◽  
Matthew V. Rockman
Keyword(s):  
Recombinant Inbred ◽  
Complex Traits ◽  
Recombinant Inbred Lines ◽  
Empirical Support ◽  
Population Based ◽  
Inbred Lines ◽  
Antagonistic Effect ◽  
Significant Qtls ◽  
C Elegans ◽  
Genomic Regions

AbstractRecent work has provided strong empirical support for the classic polygenic model for trait variation. Population-based findings suggest that most regions of genome harbor variation affecting most traits. This view is hard to reconcile with the experience of researchers who define gene functions using mutagenesis, comparing mutants one at a time to the wild type. Here, we use the approach of experimental genetics to show that indeed, most genomic regions carry variants with detectable effects on complex traits. We used high-throughput phenotyping to characterize demography as a multivariate trait in growing populations of Caenorhabditis elegans sensitized by nickel stress. We show that demography under these conditions is genetically complex in a panel of recombinant inbred lines. We then focused on a 1.4-Mb region of the X chromosome. When we compared two near isogenic lines (NILs) that differ only at this region, they were phenotypically indistinguishable. When we used additional NILs to subdivide the region into fifteen intervals, each encompassing ~0.001 of the genome, we found that eleven of intervals have significant effects. These effects are often similar in magnitude to those of genome-wide significant QTLs mapped in the recombinant inbred lines but are antagonized by the effects of variants in adjacent intervals. Contrary to the expectation of small additive effects, our findings point to large-effect variants whose effects are masked by epistasis or linkage disequilibrium between alleles of opposing effect.

Diverse sources of resistance to Spodoptera litura (F.) in groundnut

2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
M. A. Saleem ◽  
G. K. Naidu ◽  
H. L. Nadaf ◽  
P. S. Tippannavar
Keyword(s):  
Recombinant Inbred ◽  
Spodoptera Litura ◽  
Hot Spot ◽  
Recombinant Inbred Lines ◽  
Insect Pest ◽  
Inbred Lines ◽  
Leaf Damage ◽  
Botanical Variety ◽  
Resistant Genotypes ◽  
Botanical Varieties

Spodoptera litura an important insect pest of groundnut causes yield loss up to 71% in India. Though many effective chemicals are available to control Spodoptera, host plant resistance is the most desirable, economic and eco-friendly strategy. In the present study, groundnut mini core (184), recombinant inbred lines (318) and elite genotypes (44) were studied for their reaction to Spodoptera litura under hot spot location at Dharwad. Heritable component of variation existed for resistance to Spodoptera in groundnut mini core, recombinant inbred lines and elite genotypes indicating scope for selection of Spodoptera resistant genotypes. Only 29 (15%) genotypes belonging to hypogaea, fastigiata and hirsuta botanical varieties under mini core set, 15 transgressive segregants belonging to fastigiata botanical variety among 318 recombinant inbred lines and three genotypes belonging to hypogaea and fastigiata botanical varieties under elite genotypes showed resistance to Spodoptera litura with less than 10% leaf damage. Negative correlation existed between resistance to Spodoptera and days to 50 per cent flowering indicating late maturing nature of resistant genotypes. Eight resistant genotypes (ICG 862, ICG 928, ICG 76, ICG 2777, ICG 5016, ICG 12276, ICG 4412 and ICG 9905) under hypogaea botanical variety also had significantly higher pod yield. These diverse genotypes could serve as potential donors for incorporation of Spodoptera resistance in groundnut.

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