Gonadal hypoplasia in Swedish Mountain cattle and other Swedish cattle

Background

In the early 1900s, when the Swedish Mountain breed was still numerous, the breed was affected by a dramatic increase in a harmful genetic variant that causes hypoplasia of the reproductive organs (cows and bulls with small ovaries and testes, respectively, resulting in infertility in severe cases). We now know that the condition is associated with a recessive allele consisting of a translocation between chromosome 6 and chromosome 29. It is a complex structural variant whose exact sequence is not known.

The same allele is also associated with color-sidedness, a trait that has been selected for in the Mountain cattle breed. Our research shows that the allele still occurs at high frequency in the breed, probably due to this balancing selection, where the harmful effects of the allele have been offset by selection for color-sidedness. In addition, there are other alleles that cause color-sidedness but are not associated with hypoplasia.

Aim

The aim of the project is to understand the genetic causes of gonadal hypoplasia, the spread of the allele in different breeds, and how it can be managed in breeding programs.

Project description

In this thesis project, the student can investigate the breakpoints of the translocation using DNA sequencing, study the genotype and allele frequencies in additional populations using PCR, perform bioinformatic analyses of sequence data to detect the allele and estimate its frequency in publicly available data from other breeds, detect signatures of selection around the allele in sequence and genotype data, or carry out population genetic simulations to study historical selection and future breeding strategies.

Specifications

Suitable for: Animal Science, Veterinary Medicine, Biology, Bioinformatics