Milk production in sheep genetic basis and phenotype characteristics

Radostina Stoykova-Grigorova, Milena Bozhilova-Sakova, Tanya Ivanova, Maya Ignatova, Ivona Dimitrova

Abstract: Milk is a product with highly dynamic characteristics. Its composition varies according to the
breed, lactation period, nutrition, health status of the animal, as well as the conditions of milking
and storage. Investigation of genetic potential and productive traits of farm animals is essential for
every producer. The phenotypic characteristics of sheep are the result of the complex interaction of
a wide range of genetic and non-genetic factors. They are slightly influenced by traditional selection.
Therefore, it is essential to study the genetic pattern of inheritance of these traits. In the last decades of
the 20th century, several researchers have studied genetic variation in populations of different breeds of
farm animals, using genetic markers of class I, such as blood types and polymorphisms of proteins in
blood and milk. Modern methods of molecular biology make it possible to use class II genetic markers
in research to identify genetic polymorphisms in the loci of molecular markers and associate them
to certain phenotype characteristics, study the laws of organization and functioning of the genome,
decipher the mechanisms for the realization of genetic information. The obtained data from these
analyzes are successfully applied in the development of breeding programs in animal husbandry
practice, to speed up the realization of genetic progress. Some of the main major candidate genes that
have been studied related to milk productivity in sheep are: prolactin, αs1, αs2, β and κ-casein, α- and
β-lactoglobulin, PIT-1.

Keywords: candidate genes; milk production; PCR-RFLP analysis; phenotype traits; sheep breeds

Date published: 2022-04-26