Molecular Causes of Infertility in Alpacas with the Minute Chromosome Syndrome

Principal investigator:

Terje Raudsepp, PhD
Texas A and M University
College Station, Texas

Reproductive soundness and fertility have a direct bearing on the economy of the alpaca industry and the health of individual animals. Reproduction is a complex trait with a considerable genetic component, which is largely unexplored in alpacas and camelids. One of the few known reproductive disorders in alpacas with a suspected genetic component is the Minute Chromosome Syndrome (MCS). The condition is recurrently found in female alpacas and is invariably associated with sterility due to underdeveloped reproductive tract. The syndrome received its name because of the presence of one very small chromosome in the karyotypes of the affected animals, whereas the origin of this chromosome remained enigmatic for years. Recently, in course of improving the gene map and sequence assembly of the alpaca genome, we identified the minute chromosome as the smallest alpaca autosome – chromosome 36. We showed that this chromosome carries several known female fertility genes, such as zona pellucida binding protein. Despite this improved knowledge, molecular causes and underlying gene mutations of MCS still remain unknown, thus hindering efficient diagnostics and control of the condition in breeding populations. Here we propose to explore the genomes of MCS-carriers by direct DNA sequencing with the goal to discover the causative mutation and develop DNA-based tests for diagnostics. The proposed work builds upon our recently completed research on improving alpaca gene map and reference genome assembly. Another important factor for launching this work is the ongoing technological revolution in molecular biology that has made genome sequencing technically and financially feasible.

Summary of accomplishments

By generating whole genome sequences (WGS) for 14 alpacas, the project contributed to overall alpaca/llama genomics. However, due to the inadequate quality of alpaca reference genome and the genetic complexity of minute chromosome syndrome (MCS) we did not identify causative mutation or a candidate gene/marker for MCS.

Future plans

• Secure funding to improve alpaca reference genome.
• Complete the development of a qPCR test to detect animals for elevated amount of rDNA and likely MCS.
• Generate WGS for the additional 6 alpacas with confirmed MCS.
• Continue MCS research with an improved reference assembly and emerging Alpaca Genome Variant Database.