Sex determination in 6 bovid species by duplex PCR

Sexing of pre-implantation ovine embryos through polymerase chain reaction-based amplification of GAPDH, SRY and AMEL genes

The ability to identify the sex of embryo and control of sex ratio has a great commercial importance to livestock industry. Prediction of embryonic sex could be useful in the management decisions of sex selection in breeding programs. Several methods have been attempted to determine the sex but the polymerase chain reaction (PCR)-based sexing method is generally favoured, as it is cost effective, simple and reliable. The aim of the present study was to identify sex of sheep embryos produced in vitro through amplification of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), sex-determining region Y (SRY) and amelogenin genes present in genomic DNA (gDNA) of embryos through PCR. To avoid false interpretation of the result by no amplification of SRY in female embryos, a duplex PCR was approached to amplify combinedly SRY and GAPDH genes. Sex-specific blood was used in PCR as positive control. In vitro sheep embryos were produced as per standardized protocol of laboratory. Sexing of sex-specific blood and in vitro produced embryos were approached though PCR to amplify the respective genes using gDNA present in the sample without its traditional isolation. The accuracy of sex prediction for embryos was 100% by this procedure.

A high-density genetic map and molecular sex-typing assay for gerbils

We constructed a high-density genetic map for Mongolian gerbils (Meriones unguiculatus). We genotyped 137 F2 individuals with a genotype-by-sequencing (GBS) approach at over 10,000 loci and built the genetic map using a two-step approach. First, we chose the highest-quality set of 485 markers to construct a robust map of 1239 cM with 22 linkage groups as expected from the published karyotype. Second, we added an additional 5449 markers onto the map based on their genotype similarity with the original markers. We used the final marker set to assemble 1140 genomic scaffolds (containing ~ 20% of annotated genes) into a chromosome-level assembly. We used both genetic linkage and relative sequencing coverage in males and females to identify X- and Y-chromosome scaffolds and from these we designed a robust and internally-controlled PCR assay to determine sex. This assay will facilitate early stage sex-typing of embryonic and young gerbils which is difficult using current visual methods. Accession ID: Meriones unguiculatus: 10047.

Determination of sex origin of meat and meat products on the DNA basis: a review

Sex determination of domestic animal's meat is of potential value in meat authentication and quality control studies. Methods aiming at determining the sex origin of meat may be based either on the analysis of hormone or on the analysis of nucleic acids. At the present time, sex determination of meat and meat products based on hormone analysis employ gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS), and enzyme-linked immunosorbent assay (ELISA). Most of the hormone-based methods proved to be highly specific and sensitive but were not performed on a regular basis for meat sexing due to the technical limitations or the expensive equipments required. On the other hand, the most common methodology to determine the sex of meat is unquestionably traditional polymerase chain reaction (PCR) that involves gel electrophoresis of DNA amplicons. This review is intended to provide an overview of the DNA-based methods for sex determination of meat and meat products.

Sex determination of bovine preimplantation embryos by oligonucleotide microarray

The aim has been to set up a rapid and accurate microarray assay using sandwich mode for sex determination of bovine preimplantation embryos. Twelve sequence-specific oligonucleotide capture probes used to discriminate 12 samples were spotted onto the aldehyde-modified glass slides by Arrayer. The 2 recognition probes used to identify coding regions of the sex-determining region of the Y chromosome gene (SRY) and β-casein (CSN2) reference gene were coupled with biotin. The assay was optimized by using genomic DNA extracted from blood samples of known sex individuals. Polymerase chain reaction (PCR) was used to amplify the fragments in the HMG box region of SRY gene and CSN2 gene with sequence-specific primers. The sex of samples was identified by detecting both the SRY and CSN2 genes simultaneously in 2 reaction cells of microarrays, with the male having SRY and CSN2 signals and the female only CSN2. The sex of 20 bovine preimplantation embryos was determined by oligonucleotide microarray. The protocol was run with a blind test that showed a 100% (82/82) specificity and accuracy in sexing of leukocytes. The bovine embryos were transferred into 20 bovine recipients, with a pregnant rate of 40% (8/20). Three calves were born at term, and 5 fetuses were miscarried. Their sexes were fully in accordance with the embryonic sex predetermination predicted by oligonucleotide microarray. This suggests that the oligonucleotide microarray method of SRY gene analysis can be used in early sex prediction of bovine embryos in breeding programs.