Diversity in a variable-number tandem repeat from Yersinia pestis.

Area of Science:

• Microbiology
• Genetics
• Epidemiology

Background:

• Yersinia pestis is the bacterium responsible for plague.
• Understanding genetic diversity within Y. pestis is crucial for tracking outbreaks.
• Previous studies focused on gene sequence variations, which showed limited diversity.

Purpose of the Study:

• To identify and characterize novel genetic markers in Y. pestis.
• To assess the diversity and stability of a newly identified tetranucleotide repeat sequence.
• To evaluate the potential of this marker for epidemiological analysis.

Main Methods:

• Identification of a tetranucleotide repeat sequence (CAAA)(N) in Y. pestis genomes.
• Analysis of allelic diversity across 35 diverse Y. pestis strains.
• Comparison of VNTR diversity with the lcrV gene sequence diversity.
• Assessment of VNTR allele stability in replicated cultures.

Main Results:

• The (CAAA)(N) VNTR region displayed high allelic diversity (0.82) with nine alleles across 35 strains.
• In contrast, the lcrV gene showed lower haplotype diversity (0.17).
• VNTR alleles remained stable in replicated cultures, suggesting a high mutation rate contributes to diversity.
• Allelic biases were observed within plague biovars, but no single identifying alleles were found.

Conclusions:

• The (CAAA)(N) VNTR marker is highly diverse and stable under laboratory conditions.
• This VNTR marker shows promise as a high-resolution tool for Yersinia pestis epidemiological studies.
• The VNTR's location near transcriptional promoters suggests a potential role in gene regulation.