Molecular cytogenetic characterization in cattle using fish technique

Abstract

Amolecularcytogeneticinvestigationwascarriedouttoscreenforchromosomalabnormalitiesinbreedingbulls,tocharacterizetheX-andY-chromosomes and to determine the sex ratio of X-enriched semen samples. Atotal of 1072 breeding bulls belonging to 196 Jersey, 10 Holstein Friesian, 626Jerseycrossbreds,85HolsteinFriesiancrossbreds,81Kangayam,33RedSindhi, newline15Pulikulam,12Vechur,3KasargodDwarfand11non-descriptwerekaryologicallyscreened,beforesubjectingforthefrozensemenproduction.Analysis of variance revealed a significant difference (Plt0.01) in relative lengthsof the Y-chromosome between Bos indicus and Bos taurus x Bos indicus crosses.Thearm ratioandcentromericindexdifferedsignificantly(Plt0.01)betweenmeta-andsub-metacentric Ychromosomeswithinthecrossbreds. newlineA SYBR green real-time PCR method was developed to find out the sexskewness in bovine sex-sorted semen samples. The qPCR assay of PLP and SRYgenes revealed the mean values of X- and Y-bearing spermatozoa as 50.24 ± 0.65and 49.75 ± 0.62 per cent in unsorted, and 91.80 ± 0.79 and 8.20 ± 0.73 per cent inX-enriched semen samples respectively. The method was validated by a series ofrepeatabilityandreproducibilityassayswhichrevealedlowco-efficientsofvariation as 2.19 and 3.12 per cent respectively. The amplification efficiencies ofthe PLP and SRY primers were 99.25 and 98.03 per cent respectively. Thus, thismethod is demonstrated to be a reliable and inexpensive tool to evaluate the sortedsemenonroutinebasisandcalibrationofotherspermsexingtechnologies. newline newline