Brassica species include both vegetable and oilseed crops, which are very important to the daily life of common human beings. Meanwhile, the Brassica species represent an excellent system for studying numerous aspects of plant biology, specifically for the analysis of genome evolution following polyploidy, so it is also very important for scientific research. Now, the genome of Brassica rapa has already been assembled, it is the time to do deep mining of the genome data.
Brassica species belong to the Brassicaceae family, which contains about 3700 species from 338 genera, including the widely studied model plant Arabidopsis thaliana. Brassica species include both vegetable and oilseed crops that contribute about 10% of the world's vegetable production and about 12% of world's edible vegetable oil production. The diploid genomes of the six widely cultivated Brassica species are described by the famous "U's triangle" (genome A, B, C, AB, BC and AC, corresponding to B. rapa, B. oleracea, B. nigra, B. juncea, B. napus, and B. carinata, respectively. The A genome species, B. rapa, is a major vegetable and also an oil crop in Asia and Europe. Because of their importance as crops and as models to study complex genome hybridization and polyploidization, genetic and genomic research on Brassicas has intensified over recent years, generating ever increasing sets of data, such as Brassica genome sequences, genetic markers, expressed sequence tags (ESTs) and quantitative trait loci (QTLs).
The recently completed initial assembly of the whole genome sequence of the B. rapa cultivar line 'Chiifu-401' is now available.
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Microsatellite markers
Microsatellites, also known as Simple Sequence Repeats (SSRs) or short tandem repeats (STRs), are repeating sequences of specific DNA which contains mono-, di-, tri-, or tetra-, penta- or hexa- tandem repeats such as (A)n, (CA)n, (GA)n, (GTA)n, (ATT)n, (GATA)n, (ATTTT)n, (ACGTCG)n. Genomes are scattered with these repeats. Repeats of longer units form minisatellites or satellite DNA. With the discovery of tandem iterations of simple sequence motifs, the term microsatellites was further coined.
Microsatellites can be analysed using different protocols as per the lab’s budget, labour and speed required. In the past years different protocols have been tested and standardised for population studies, polymorphism estimations, genetic mapping etc.
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