A Comparative Assessment Study on the Prolactin Gene as a Genetic Marker for Milk Production in High Milk-Producing Mammals through Phylogenetic Analysis

Abstract

The prolactin (PRL) gene is a focus in milk-related studies for high-yielding ruminants like dairy cows, water buffaloes, dairy goats, and sheep. Despite its recognition as a genetic marker for milk traits, little is known about the specific genetic features enabling heightened milk production. The PRL nucleotide sequence of the ruminants and the human outgroup were obtained from the GenBank database. Using the MEGA 7 software, amino acid translation was conducted and multisequence analysis was done, allowing for the construction of phylogenetic trees. In both trees, ruminants were consistently clustered together forming pairings of the dairy cow: water buffalo and the dairy goat: sheep. In the nucleotide sequences of all the involved taxa, cytosine and guanine were the unanimous most and least comprised nucleotide. In the amino acid composition, the unanimous most and least amino acid percentages were leucine and tryptophan, respectively. Leucine, being the highest comprised, was substantiated by related studies stating that such amino acid is highly involved in milk production and yield. Glycine percentages were found to be higher in ruminants than in humans, providing a possible reasoning for such milk-yield disparity in the involved taxa.