Copy number variation (CNV) is a phenomenon in which sections of the genome, ranging from one kilo base pair (Kb) to several million base pairs (Mb), are repeated and the number of repeats vary between the individuals in a population. It is an important source of genetic variation in an individual which is now being utilized rather than single nucleotide polymorphisms (SNPs), as it covers the more genomic region. CNVs alter the gene expression and change the phenotype of an individual due to deletion and duplication of genes in the copy number variation regions (CNVRs). Earlier, researchers extensively utilized SNPs as the main source of genetic variation. But now, the focus is on identification of CNVs associated with complex traits. With the recent advances and reduction in the cost of sequencing, arrays are developed for genotyping which cover the maximum number of SNPs at a time that can be used for detection of CNVRs and underlying quantitative trait loci (QTL) for the complex traits to accelerate genetic improvement. CNV studies are also being carried out to understand the evolutionary mechanism in the domestication of livestock and their adaptation to the different environmental conditions. The main aim of the study is to review the available data on CNV and its role in genetic variation among the livestock.

Increased concern on greenhouse gas emission, concomitant global warming and decreasing fossil fuels have created the necessity to find an alternative source of energy for the transportation vehicles. Biodiesels is an alternative renewable fuel source, which releases less carbon dioxide, carbon monoxide, sulfur and nitrogen oxides upon combustion. These environmental friendly features of biodiesel make it a potential alternative to the conventional one. Biodiesel can be extracted from the edible or non -edible source of triglycerides. During this extraction process, crude glycerol (CG) is obtained at the rate of 10% as a byproduct of trans-esterification reaction. Chemically, CG so obtained is composed of catalysts, salts and fatty acids. Purification of CG to >95% involves the cost (0.28 USD/L production) and time consuming process. Hence, economical management of CG is the need of hour, one such alternative way is its entry in animal food chain as an energy source. Basically, glycerol is a glycogenic intermediate product of fat digestion converted to glucose by the action of key enzyme glycerol kinase. The CG undergo glycolysis and TCA cycle to liberate ATP. The digestible and metabolizable energy content of CG are comparable with the commonly used cereal grains in livestock feeding. Thus, CG acts as a bridging gap between the biodiesel industry and livestock production. Studies have showed that CG