Pig Screening Test Detects up to 2x as Many Chromosome Translocatons Compared to Regular Karyotyping

Read the paper here: https://www.mdpi.com/2073-4409/10/2/250

Pigs are the world's leading source of meat protein and demand is rising, especially in south east Asia.

However significant economic loss and environmental damage can be incurred if boars used for artificial insemination (AI) are sub-fertile. Growing evidence suggests that regular semen analysis is an unreliable tool for diagnosing sub-fertility. Indeed, litter size and farrowing rate is more useful.

But the time such data becomes available, however, any affected boar will have been in service for some time, with significant financial and environmental losses incurred.

Reciprocal chromosome translocation (RTs) are the leading cause of porcine hypoprolificacy, reportedly present in 0.47% of AI boars. Traditional standard karyotyping, however, relies on animal specific expertise and does not detect more subtle (cryptic) translocations. Previously, Becky et al reported development of a multiple hybridisation fluorescence in situ hybridisation (FISH) strategy; here, we report on its use in 1641 AI boars.

A total of 15 different RTs were identified in 69 boars, with four further animals XX/XY chimeric, 4.5% thus had a chromosome abnormality. Revisiting cases with both karyotype and FISH information, we reanalysed captured images, asking whether the RT was detectable by karyotyping alone. The results suggest that chromosome translocations in boars may be significantly under-reported. We therefore desperately need pre-emptive screening by this method before a boar enters a breeding programme.