Mapping of 31 horse genes in BACs by FISH.

The research article is about mapping the location of 31 specific genes in a horse genome, solidifying the understanding of horse-human genetic similarities. It enhances the resolution of the comparative gene map between horses and humans.

Methodology

• The process began with screening an INRA equine genomic BAC library. A BAC (Bacterial Artificial Chromosome) library is a collection of cloned bacterial DNA sequences which represent the entire DNA sequence of a particular organism, in this case, a horse.
• The screening was conducted through PCR (Polymerase Chain Reaction), using 24 primer sets created for the 30UTR of EST (Expressed Sequence Tag) clones from a 60-day horse embryo cDNA (Complementary DNA) library. Primers are short DNA fragments that serve as starting point for DNA synthesis, making the creation of multiple copies of a particular DNA sequence simpler and faster.
• In addition to the PCR screening, 6 CATS primer sets and 1 UM-STS primer set were utilised.
• After the clone was identified, its identity got confirmed through cycle sequencing on an Applied Biosystem’s Prism Genetic Analyzer.
• After the sequence data was obtained, sequences were then compared with ones in GenBank using BLAST searches. GenBank is an accessible database of all publicly available nucleotide sequences and their protein translations, while BLAST (Basic Local Alignment Search Tool) is an algorithm used for comparing primary biological sequence information.
• Metaphase chromosome preparation and fluorescence in situ hybridization (FISH), a technique used to detect and localize specific DNA sequences on chromosomes, were carried out as per previous methods.

Results

• They obtained the data on the clones, including information such as the INRA clone ID number, gene symbol, gene name, horse chromosome map position, clone GenBank accession number, and the position of the human gene homolog chromosome map.
• The locations of the thirty-one horse genes matched up with existing human-horse gene homologies as predicted by ZOO-FISH and synteny mapping studies. ZOO-FISH (ZOOlogical Fluorescence In Situ Hybridization) refers to application of FISH techniques to different species to identify homologies and changes in genome structure.
• The position of gene TCRG on ECA4p defined a new similarity with HSA7p, starkly increasing the resolution of the human-horse comparative gene map.