3 April 1998

Key role for rare breeds in pinpointing pig genes

RARE pig breeds could be used to improve modern genotype performance now that researchers have pinpointed which genes are responsible for changing production traits such as backfat level.

Researchers at Roslin Institute, Edinburgh, made the discovery when crossing Chinese Meisham pigs and Large Whites. Meisham are inferior to Large Whites for growth rate and fatness, but superior for litter size.

According to researcher, Grant Walling, the diverse character of each breed has helped identify chromosomes which affect performance and from which breed they originate during a study of 390 F2 crossbred pigs.

"Meishams chromosome seven had a significant effect on reducing P2 backfat levels which was unexpected – the breed is noted for being fat. Its thought that a number of small genes are overwhelming that effect, but when chromosome seven is introduced to a Large White it may reduce back fat levels."

In the trial using 13 DNA-based markers, P2 backfat was reduced by 1.8mm, whilst growth rates were improved by 25g a day to weaning and 50g a day from 30-85kg liveweight.

"These results suggest that less advanced breeds can contribute valuable genetic variation to commercially improved genotypes. Rare breeds may still have a part to play in modern pig breeding." &#42