Submitted to: Molecular and General Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/1996
Publication Date: N/A
Citation: Interpretive Summary: Vast amounts of hereditary material (DNA) is packaged inside cells around structures called histones. Histone genes produce proteins which help make up the various types of histones. These genes exist in many copies, called gene families, and have much variation among them. The authors have analyzed some of these variant genes from wheat, barley and soybean. They were able to single-out and monitor specific genes from the family. The authors found that the histone genes are spliced and processed in similar places among the different crops, but that the length of the region cut out of the gene region varies among crops and even within a crop. Because histones themselves are thought to play a significant role in affecting expression of other genes and because the variation of histone gene structure is thought to affect their own expression, this work will help scientists understand relationships between gene structure and function, and gene regulation. Understanding complex gene families such as this, and understanding how subtle variations among the genes within the family affects expression, may help us to understand complexities of gene expression affected by genotypic background and environment. This work may help us to understand some of the complexities of quantitative trait expression.
Technical Abstract: Several variants of the replacement histone H3 genes from soybean, barley and wheat have been cloned and sequenced. Analysis of segregating populations in barley and soybean, as well as analysis of isolated clones from a soybean genomic library suggested that these genes are dispersed throughout the genome. Several genes contained introns located in similar positions, but of different length and sequence. Comparison of mRNA levels in different tissues revealed that the intron-containing and intronless genes have different expression patterns. Distribution of the introns in the histone H3 genes across several plant species suggested that some of the introns might have been lost during the evolution of the gene family. Sequence divergence among introns and gene-flanking sequences in cloned gene variants allowed us to use them as specific probes for targeting individual gene copies, and to analyze genomic distribution of these variants across a range of genotypes.