Deep small RNA-Seq reveals important mircoRNAs in lactating mammary gland of the two sheep breeds with different milk performance

Micro RNA (miRNA) is a type of non-coding RNA with the generally size of about 22 nucleotides and it has been proved to have an important role in various biological process of cell. In several species, miRNA has been revealed to be important roles in the activity of the mammary gland (MG), but the miRNAs mechanisms involved in the genetic regulation of ewe milk component synthesis are not completely understood. In the study, microstructures and the expression profile of miRNAs was investigated using small RNA-Seq in MG parenchyma at peak lactation, derived from two sheep breeds with different milk production characteristics, the low-lactating yield Gansu Alpine Merino (GAM, n = 9) and high-lactating yield Small-tailed Han sheep (STH, n = 9).