Novel method for identification of the lethal mutation in bovine APAF1 gene and its preliminary prevalence in Polish Holstein-Friesian bulls

Development of alternative diagnosis of HH1, HH3, HH5 and HCD fertility haplotypes and subfertility syndrome in cattle

The increasing prevalence of hereditary anomalies in Holstein cattle populations presents a pressing issue, leading to concerns such as embryonic mortality and the birth of non-viable offspring. This study addresses the urgency of managing harmful genetic mutations in Holstein cattle by developing alternative diagnostic methods. The research aims to devise effective means to diagnose fertility haplotypes HH1, HH3, HH5, HCD and BY and subfertility syndrome in cattle. To achieve this goal, a range of molecular genetic techniques were employed, including Tetra-Primer ARMS-PCR methods, PCR-RFLP analysis and allele-specific PCR. These methods facilitated the identification of heterozygous carriers of various fertility haplotypes and subfertility syndrome in Holstein cows and servicing bulls. The study reveals the prevalence of these genetic defects within the Republic of Kazakhstan's cattle population. HH1, HH3, HH5, HCD and BY fertility haplotypes were found to have occurrence rates ranging from 1.4% to 16.6%, with subfertility syndrome detected in 4.5% of Simmental bulls. The practical significance of this research lies in its contribution to genetic monitoring and management strategies for Holstein cattle populations. By introducing affordable, rapid and accurate diagnostic methods, such as the T-ARMS-PCR, the study provides a valuable tool for controlling and mitigating the spread of harmful genetic mutations, ultimately improving the overall genetic health and productivity of Holstein cattle in the region. This research addresses a critical need in the cattle breeding industry and underscores the importance of genetic monitoring to ensure the long-term viability and sustainability of Holstein cattle populations.

Allele Frequency of APAF1 Mutation in Holstein Cattle in Brazil

APAF1 is an autosomal recessive inherited mutation, associated with Holstein haplotype 1 (HH1) and characterized by a substitution of cytosine for a thymine (c.1741C>T) in chromosome 5. The mutation causes fetal and embryonic loss, between 60 and 200 days of gestation, and reduced conception rate. The ARMS-PCR is considered a simple and low-cost method to determine single nucleotide polymorphism (SNP) with no need for genetic sequencing of the animal genome. This study aimed to verify the allelic frequency of APAF1 mutation in Brazilian Holstein cattle. A total of 248 Holstein DNA samples (210 cows and 38 bulls) were analyzed, and synthetic genes were manufactured to validate the primers developed by the authors. All animals assessed in this study were classified as wild-type for APAF1 mutation. The primers and protocol developed for the ARMS-PCR technique work with 100% specificity and efficiency since the amplicon formations are as expected according to the genotypes. In conclusion, the mutation responsible for APAF1 was not detected in the Brazilian Holstein cattle population assessed in this prevalence study, although it is not possible to affirm that APAF1 does not occur in Brazilian Holstein animals. The tetra-primer ARMS-PCR protocol for APAF1 mutation that has been validated here may be a relatively simple and economical method to determine the animals' genotype.