DNA-Based Genetic Markers for Rapid Cycling Brassica Rapa (Fast Plants Type) Designed for the Teaching Laboratory

We have developed DNA-based genetic markers for rapid cycling Brassica rapa (RCBr), also known as Fast Plants. Although markers for B. rapa already exist, ours were intentionally designed for use in a teaching laboratory environment. The qualities we selected for were robust amplification in PCR, polymorphism in RCBr strains, and alleles that can be easily resolved in simple agarose slab gels. We have developed two single nucleotide polymorphism (SNP) based markers and 14 variable number tandem repeat (VNTR)-type markers spread over four chromosomes. The DNA sequences of these markers represent variation in a wide range of genomic features. Among the VNTR-type markers, there are examples of variation in a non-genic region, variation within an intron, and variation in the coding sequence of a gene. Among the SNP-based markers there are examples of polymorphism in intronic DNA and synonymous substitution in a coding sequence. Thus these markers can serve laboratory exercises in both transmission genetics and molecular biology

1971: Abilene Christian College Bible Lectures - Full Text

WORLD EVANGELISM Being the Abilene Christian College Annual Bible Lectures 1971 Published by ABILENE CHRISTIAN COLLEGE BOOK STORE ACC Station Abilene, Texas 7960

Mapping the Anthocyaninless (anl) Locus in Rapid-Cycling Brassica rapa (RBr) to Linkage Group R9

<p>Abstract</p> <p>Background</p> <p>Anthocyanins are flavonoid pigments that are responsible for purple coloration in the stems and leaves of a variety of plant species. <it>Anthocyaninless </it>(<it>anl</it>) mutants of <it>Brassica rapa </it>fail to produce anthocyanin pigments. In rapid-cycling <it>Brassica rapa</it>, also known as Wisconsin Fast Plants, the anthocyaninless trait, also called non-purple stem, is widely used as a model recessive trait for teaching genetics. Although anthocyanin genes have been mapped in other plants such as <it>Arabidopsis thaliana</it>, the <it>anl </it>locus has not been mapped in any <it>Brassica </it>species.</p> <p>Results</p> <p>We tested primer pairs known to amplify microsatellites in <it>Brassicas </it>and identified 37 that amplified a product in rapid-cycling <it>Brassica rapa</it>. We then developed three-generation pedigrees to assess linkage between the microsatellite markers and <it>anl</it>. 22 of the markers that we tested were polymorphic in our crosses. Based on 177 F₂offspring, we identified three markers linked to <it>anl </it>with LOD scores ≥ 5.0, forming a linkage group spanning 46.9 cM. Because one of these markers has been assigned to a known <it>B. rapa </it>linkage group, we can now assign the <it>anl </it>locus to <it>B. rapa </it>linkage group R9.</p> <p>Conclusion</p> <p>This study is the first to identify the chromosomal location of an anthocyanin pigment gene among the <it>Brassicas</it>. It also connects a classical mutant frequently used in genetics education with molecular markers and a known chromosomal location.</p

The First Data Release of the Sloan Digital Sky Survey

The Sloan Digital Sky Survey has validated and made publicly available its First Data Release. This consists of 2099 square degrees of five-band (u, g, r, i, z) imaging data, 186,240 spectra of galaxies, quasars, stars and calibrating blank sky patches selected over 1360 square degrees of this area, and tables of measured parameters from these data. The imaging data go to a depth of r ~ 22.6 and are photometrically and astrometrically calibrated to 2% rms and 100 milli-arcsec rms per coordinate, respectively. The spectra cover the range 3800--9200 A, with a resolution of 1800--2100. Further characteristics of the data are described, as are the data products themselves.Comment: Submitted to The Astronomical Journal. 16 pages. For associated documentation, see http://www.sdss.org/dr

The Gene Encoding Dihydroflavonol 4-Reductase Is a Candidate for the anthocyaninless Locus of Rapid Cycling Brassica rapa (Fast Plants Type).

Rapid cycling Brassica rapa, also known as Wisconsin Fast Plants, are a widely used organism in both K-12 and college science education. They are an excellent system for genetics laboratory instruction because it is very easy to conduct genetic crosses with this organism, there are numerous seed stocks with variation in both Mendelian and quantitative traits, they have a short generation time, and there is a wealth of educational materials for instructors using them. Their main deficiency for genetics education is that none of the genetic variation in RCBr has yet been characterized at the molecular level. Here we present the first molecular characterization of a gene responsible for a trait in Fast Plants. The trait under study is purple/nonpurple variation due to the anthocyaninless locus, which is one of the Mendelian traits most frequently used for genetics education with this organism. We present evidence that the DFR gene, which encodes dihyroflavonol 4-reductase, is the candidate gene for the anthocyaninless (ANL) locus in RCBr. DFR shows complete linkage with ANL in genetic crosses with a total of 948 informative chromosomes, and strains with the recessive nonpurple phenotype have a transposon-related insertion in the DFR which is predicted to disrupt gene function

Genes in the interval containing <i>anthocyaninless</i>.

<p>Genes in the interval containing <i>anthocyaninless</i>.</p

Primers used to characterize the <i>DFR</i> gene.

<p>Primers used to characterize the <i>DFR</i> gene.</p

Genetic linkage map of chromosome A09 including DNA markers tightly linked to the <i>anthocyaninless</i> (<i>ANL</i>) locus.

<p>Genotype data are from 126 BC1 progeny. Distances are in Kosambi centimorgans and all linkages have a LOD > 3.0.</p

Development of a PCR test of the <i>anl</i> mutation for the teaching laboratory.

<p>(A0 When DNA from a heterozygote is used as PCR template, wild type and mutant alleles cannot be simultaneously amplified. Gel contains products of duplicate reactions of Purple Stem, Hairy (PH), Nonpurple Stem, Yellow Green Leaf (NP), and a hybrid of the two (F1). (B) A PCR test that detects the mutant (N) and wild type (P) alleles in separate reactions in plants grown from Carolina Biological Supply seeds. PCR is as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0161394#pone.0161394.g004" target="_blank">Fig 4</a>.D. Lanes: (1) DNA ladder, (2) Nonpurple Stem, Yellow Green Leaf, (3) Purple Hairy, (4) F₁ generation, (5–8) F₂ seedlings with nonpurple phenotype, (9–20) F₂ seedlings with purple phenotype.</p