Effect of moxidectin selection on the genetic variation within Cylicocyclus nassatus based on amplified fragment length polymorphism (AFLP).

The research investigates the impact of the drug moxidectin on the genetic diversity of Cylicocyclus nassatus, a common intestinal worm in horses. Using a technique called Amplified Fragment Length Polymorphism (AFLP), the study found that moxidectin reduces the variation in the worm’s genes.

Research Methodology

• This study used AFLP (Amplified Fragment Length Polymorphism) technique to explore the genetic variations within Cylicocyclus nassatus, a key intestinal nematode in horses. AFLP is a technique that uses PCR (polymerase chain reaction) to amplify DNA fragments and then analyze their length variations.
• The researchers collected DNAs from 30 individual male worms from two different populations. The first being an avermectin-milbemycin (AM)-naive population (Population-S) and the second being a population derived from Population-S, but treated with moxidectin 21 times (Population-Mox).
• Three selective primer pairs were used for each worm, yielding a total of 229 AFLP markers. These markers allowed the analysis of genetic variation within both populations.

Research Findings

• The study found a high degree of genetic variation within both populations of the worm using all three primer combinations. This suggests that the genetic makeup of the C. nassatus worm is highly variable.
• The research found that the use of moxidectin caused a significant reduction in genetic diversity within the worm population. This was evidenced by the analysis of AFLP markers for two primer combinations. However, the reduction was not evident with the third primer combination.
• Despite observing a drop in genetic diversity with moxidectin application, a dendrogram (a branching diagram showing the relationship among different populations) did not show a distinct classification of individuals into separate groups.
• It was concluded that the nematode C. nassatus exhibits great genetic diversity within populations and the application of moxidectin has significant impact on its genetic composition.

Significance of the study

• This study contributes to the limited literature on the molecular genetics of Cyathostomins, one of the most important intestinal nematodes in horses.
• The results provide insights into how the application of drugs such as moxidectin can alter the genetic makeup of the worm population, which may have implications for treatment or control strategies for these parasites.