ABSTRACT
The plant Arabidopsis thaliana (Arabidopsis) has become an important model species for the study of many aspects of plant biology. The relatively small size of the nuclear genome and the availability of extensive physical maps of the five chromosomes provide a feasible basis for initiating sequencing of the five chromosomes. The YAC (yeast artificial chromosome)-based physical map of chromosome 4 was used to construct a sequence-ready map of cosmid and BAC (bacterial artificial chromosome) clones covering a 1.9-megabase (Mb) contiguous region, and the sequence of this region is reported here. Analysis of the sequence revealed an average gene density of one gene every 4.8 kilobases (kb), and 54% of the predicted genes had significant similarity to known genes. Other interesting features were found, such as the sequence of a disease-resistance gene locus, the distribution of retroelements, the frequent occurrence of clustered gene families, and the sequence of several classes of genes not previously encountered in plants.
Subject(s)
Arabidopsis/genetics , Chromosome Mapping , Genome, Plant , Chromosomes, Artificial, Yeast , Genes, Plant/physiology , Multigene Family , Plant Proteins/genetics , Sequence Analysis, DNAABSTRACT
We report the sequence analysis of a 78,601 bp DNA segment on the left arm of chromosome II of Saccharomyces cerevisiae. This 78.6 kb segment spans the region from the start of a subtelomeric Y' element up to the ILS1 gene. It contains 49 open reading frames (ORFs) with more than 100 amino acids length including 14 internal and five overlapping ORFs. The gene density, excluding the internal ORFs, was calculated as one ORF per 2.2 kb. Eight ORFs (PKC1, TyA, TyB, ATP1, ROX3, RPL17a, PET112 and ILS1) correspond to previously characterized genes. ORF YBL0718 was identified as CDC27; YBL0706 as TEL1. Four other ORFs show strong similarities to already known genes. The gene product of YBL0838 is 60% identical to the ribosomal protein RPL32 from rat, mouse and man. YBL0701 encodes a protein with significant similarity to the initiation factor eIF2 associated p67 glycoprotein from rat. Eight ORFs were disrupted and the resulting yeast strains analysed with respect to their phenotype.
