Congratulations to Carla Ribeiro for achieving a maximum 20 out of 20 in her MSc! - 13/04/2021

Carla's MSc was awarded by UTAD in Portugal and performed here in Kent.

Chromosomes and fertility in Sus scrofa and Bos taurus: an analysis of progenitors and embryos

Efficient breeding of livestock species, such as pig and cattle, has become a priority due to the rising global food demand fuelled by the human population increase. The number of people on the planet expected to rise from 7.8 billion (currently) to 9.7 billion in 2050. To optimize breeding efficiency, and produce individuals with high genetic merit and so capable to produce more using fewer resources, new technologies have been developed. These include in vitro production (IVP) of embryos and preimplantation genetic testing (PGT). Producing livestock embryos by IVP using sperm and oocytes from elite parents can dramatically increase the breeder’s ability to select the most promising animals. This can lead to rapid improvement of the target livestock population. One drawback of IVP however is that they suffer from a high incidence of chromosomal abnormalities such as aneuploidy. This can lead to clinical syndromes, infertility, and miscarriages, but can be detected through preimplantation genetic testing for aneuploidy (PGT-A).

In this dissertation, three different PGT-A algorithms: Karyomapping, BAF/LRR and Gabriel-Griffin plots, were applied on two cattle embryo DNA marker databases to investigate aneuploidy presence, class, parental and mechanistic origin, overall and as related to embryo sex and quality. In pigs, for the first time in this species, a novel IVP protocol was optimised and applied on selected donors to produce embryos, which could be screened by the same three PGT-A algorithms mentioned above.