Segregation distortion in Arabidopsis C24/Col-0 and Col-0/C24 recombinant inbred line populations is due to reduced fertility caused by epistatic interaction of two loci.
ABSTRACT A new large set of reciprocal recombinant inbred lines (RILs) was created between the Arabidopsis accessions Col-0 and C24 for quantitative trait mapping approaches, consisting of 209 Col-0 x C24 and 214 C24 x Col-0 F(7 )RI lines. Genotyping was performed using 110 evenly distributed framework single nucleotide polymorphism markers, yielding a genetic map of 425.70 cM, with an average interval of 3.87 cM. Segregation distortion (SD) was observed in several genomic regions during the construction of the genetic map. Linkage disequilibrium analysis revealed an association between a distorted region at the bottom of chromosome V and a non-distorted region on chromosome IV. A detailed analysis of the RILs for these two regions showed that an SD occurred when homozygous Col-0 alleles on chromosome IV coincided with homozygous C24 alleles at the bottom of chromosome V. Using nearly isogenic lines segregating for the distorted region we confirmed that this genotypic composition leads to reduced fertility and fitness.
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ABSTRACT: In flowering plants, pollen grains germinate to form pollen tubes that transport male gametes (sperm cells) to the egg cell in the embryo sac during sexual reproduction. Pollen tube biology is complex, presenting parallels with axon guidance and moving cell systems in animals. Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac signals. A well-documented recognition system occurs between pollen grains and the stigma in sporophytic self-incompatibility, where both receptor kinases in the stigma and their peptide ligands from pollen are now known. Complex mechanisms act to precisely target the sperm cells into the embryo sac. These events initiate double fertilization in which the two sperm cells from one pollen tube fuse to produce distinctly different products: one with the egg to produce the zygote and embryo and the other with the central cell to produce the endosperm.Annual Review of Cell and Developmental Biology 02/2002; 18:81-105. · 17.98 Impact Factor
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ABSTRACT: The annotated Arabidopsis genome sequence was exploited as a tool for carrying out comparative analyses of the Arabidopsis and Capsella rubella genomes. Comparison of a set of random, short C. rubella sequences with the corresponding sequences in Arabidopsis revealed that aligned protein-coding exon sequences differ from aligned intron or intergenic sequences in respect to the degree of sequence identity and the frequency of small insertions/deletions. Molecular-mapped markers and expressed sequence tags derived from Arabidopsis were used for genetic mapping in a population derived from an interspecific cross between Capsella grandiflora and C. rubella. The resulting eight Capsella linkage groups were compared to the sequence maps of the five Arabidopsis chromosomes. Fourteen colinear segments spanning approximately 85% of the Arabidopsis chromosome sequence maps and 92% of the Capsella genetic linkage map were detected. Several fusions and fissions of chromosomal segments as well as large inversions account for the observed arrangement of the 14 colinear blocks in the analyzed genomes. In addition, evidence for small-scale deviations from genome colinearity was found. Colinearity between the Arabidopsis and Capsella genomes is more pronounced than has been previously reported for comparisons between Arabidopsis and different Brassica species.Plant physiology 07/2004; 135(2):735-44. · 6.56 Impact Factor
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ABSTRACT: Two of Mendel's three laws were quickly discarded as information on the organization and transmission of genes accumulated at the beginning of this century, but his law of segregation has shown remarkable staying power. In fact, within most of population genetic theory for sexual diploids is buried the tacit assumption that heterozygous alleles are represented in gametes in a 1:1 ratio. Nevertheless, there is a small, but important, group of genetic systems that subvert the law of segregation, and show 'meiotic drive'.Trends in Genetics 07/1993; 9(6):205-10. · 9.77 Impact Factor