The KoreaBrassicaGenome Project: a Glimpse of theBrassicaGenome Based on Comparative Genome Analysis WithArabidopsis

摘要

A complete genome sequence provides unlimited information in the sequenced organismas well as in related taxa. According to the guidance of the Multinational BrassicaGenome Project (MBGP), the Korea Brassica Genome Project (KBGP) is sequencingchromosome 1 (cytogenetically oriented chromosome #1) ofBrassica rapa. Wehave selected 48 seed BACs on chromosome 1 using EST genetic markers and FISHanalyses. Among them, 30 BAC clones have been sequenced and 18 are on the way.Comparative genome analyses of the EST sequences and sequenced BAC clones fromBrassicachromosome 1 revealed their homeologous partner regions on theArabidopsisgenome and a syntenic comparative map betweenBrassicachromosome 1 andArabidopsischromosomes.In silicochromosome walking and clone validation havebeen successfully applied to extending sequence contigs based on the comparativemap and BAC end sequences. In addition, we have defined the (peri)centromericheterochromatin blocks with centromeric tandem repeats, rDNA and centromericretrotransposons. In-depth sequence analyses of five homeologous BAC clones andanArabidopsischromosomal region reveal overall co-linearity, with 82% sequencesimilarity. The data indicate that theBrassicagenome has undergone triplication andsubsequent gene losses after the divergence ofArabidopsisandBrassica. Based on in-depthcomparative genome analyses, we propose a comparative genomics approachfor conquering theBrassicagenome. In 2005 we intend to construct an integratedphysical map, including sequence information from 500 BAC clones and integrationof fingerprinting data and end sequence data of more than 100 000 BAC clones.The sequences have been submitted to GenBank with accession numbers: 10 204BAC ends of the KBrH library (CW978640–CW988843); KBrH138P04, AC155338;KBrH117N09, AC155337; KBrH097M21, AC155348; KBrH093K03, AC155347;KBrH081N08, AC155346; KBrH080L24, AC155345; KBrH077A05, AC155343;KBrH020D15, AC155340; KBrH015H17, AC155339; KBrH001H24, AC155335;KBrH080A08, AC155344; KBrH004D11, AC155341; KBrH117M18, AC146875;KBrH052O08, AC155342.