genome sequencing in is thaliana

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    A. thaliana is a small flowering plant that is

    widely used as a model organism in plant

    biology.

    Member of the mustard (Brassicaceae) familyCommon name- Wall cress or Mouse-ear cress

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    Small genome -125 Mb, sequenced in the year2000

    Extensive genetic and physical maps of all 5chromosomes

    A rapid life cycle (about 6 weeks fromgermination to mature seed)

    Prolific seed production and easy cultivation inrestricted space.

    Efficient transformation methods utilizingAgrobacterium tumefaciens.

    A large number of mutant lines and genomicresources many of which are available fromStock Centers(ABRC, Ohio;NASC,UK)

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    A. thaliana was discovered by Johannes Thal

    in the Harz mountains in Germany

    He called it Pilosella siliquosa, later name

    changed toA. thaliana F. Laibach first summarized the potential of

    A. thaliana as a model organism for genetics

    in 1943.

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    Bacterial artificial chromosome (BAC), phage

    (P1) and Transformation-competent artificial

    chromosome (TAC) libraries as the primary

    substrates for sequencing.

    Physical maps of the genome of accession

    Columbia was first assembled by BAC clones.

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    Total length of sequenced regions, which

    extend from telomeres to the 180-base-pair

    centromeric repeats, is 115,409,949 (bp)

    The unsequenced centromeric and rDNArepeat regions measure roughly 10

    megabases (Mb), yielding a genome size of

    about 125Mb

    Features such as gene density, expressionlevels and repeat distribution are very

    consistent across the five chromosomes

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    Arabidopsis has a significantly greater extent

    of tandem gene duplications and segmental

    duplications, which account for its larger

    gene set.

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    To assess the similarities and differences of

    the Arabidopsis gene complement compared

    with other sequenced eukaryotic genomes,

    functional categories were assigned to thecomplete set of Arabidopsis genes.

    The functions of 69% of the genes were

    classified according to sequence similarity to

    proteins of known function in all organisms.

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    17.6% and 11.4% of gene products were

    predicted to be targeted to the secretory

    pathway and mitochondria in Arabidopsis

    14% of the gene products are likely to betargeted to the chloroplast

    Significant proportion of genes with

    predicted functions involved in metabolism,

    gene regulation and defence.

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    The Arabidopsis genome sequence provides a

    complete view of chromosomal organization

    and clues to its evolutionary history

    The majority of the Arabidopsis genome isrepresented in duplicated segments, it

    appears most likely that Arabidopsis, like

    maize, had a tetraploid ancestor.

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    To identify commonly occurring changes in

    genome microstructure.

    Enables the development of new molecular

    markers for genetic mappingComparative analysis was done between

    accession Columbia (Col-0) and accession

    Landsberg erecta

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    They identified two classes of differences

    between the sequences: single nucleotide

    polymorphisms (SNPs), and insertion-

    deletions (InDels). Sequence polymorphisms between accessions

    of Arabidopsis in both coding and non-coding

    regions.

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    Transposons in Arabidopsis account for at

    least 10% of the genome

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    For more information log on to:

    http://www.arabidopsis.org/index.jsp

    Analysis of the genome sequence of the

    flowering plantArabidopsis thaliana :Nature:408

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