Dialect-I, species-specific repeated DNA sequence from barley, Hordeum vulgare

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• Repetitive DNA sequences are crucial components of eukaryotic genomes.
• Understanding the distribution and characteristics of repetitive DNA can provide insights into genome evolution and organization.
• Barley (Hordeum vulgare) possesses a complex genome with numerous repetitive elements.

Purpose of the Study:

• To clone and characterize the species-specific repetitive DNA sequence, Dialect-1, in barley.
• To investigate the genomic distribution and copy number of Dialect-1 in barley and related species.
• To assess the potential of Dialect-1 as a molecular marker for taxonomic and genetic studies.

Main Methods:

• Southern blot hybridization to analyze DNA.
• In situ hybridization to determine chromosomal location.
• Cloning and subcloning of DNA fragments from a lambda phage library.
• Comparative genomic analysis across different Hordeum species and other cereals.

Main Results:

• Dialect-1 is a repetitive DNA sequence dispersed throughout all barley chromosomes with approximately 5,000 copies per genome.
• Related DNA fragments were identified, suggesting a large full-length genomic repeat structure.
• Dialect-1 is conserved in Hordeum vulgare and its subspecies agriocrithon and spontaneum but rearranged and reduced in copy number in H. bulbosum and H. murinum.
• The repeat is absent in several wild barley species, wheat, rye, oats, and maize.

Conclusions:

• Dialect-1 is a species-specific repetitive DNA element in barley with a defined genomic distribution.
• The characterized repeat can be utilized as a molecular marker for barley taxonomic studies.
• Dialect-1 aids in the identification of barley chromosomes within interspecies hybrids, offering insights into Hordeum phylogeny.