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Effects of bovine
prolactin gene polymorphism within exon 4 on milk related
traits and genetic trends in Iranian Holstein bulls
Yousef Mehmannavaz1*,
Cyrus Amirinia2, Mortaza Bonyadi3 and
Rasoul Vaez Torshizi4
1Department
of Animal Science, Faculty of Agriculture, Science and
Research Branch, Islamic Azad University, Tehran, Iran.
2Department
of Animal Biotechnology, Animal Science Research Institute
of Iran, Karaj, Iran.
3Center
of Excellence for Biodiversity, University of Tabriz,
Tabriz, Iran.
4Animal
Science Department, Faculty of Agriculture, Tarbiat Modares
University, Tehran, Iran.
*Corresponding author. E-mail:
mehman10@yahoo.com.
Tel: +98 914 4317572. Fax: +98 421 3254506.
Accepted
10 August, 2009 |
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In this
study, polymorphism of prolactin
gene was analyzed as a candidate gene
responsible for variation and genetic trends in milk
yield and composition traits. Genomic DNAs were extracted
from 268 semen samples belonged to Iranian Holstein bulls.
Genotyping for the prolactin gene using PCR-RFLP technique
and RsaI
restriction
endonuclease
showed a mutation in 294-bp fragment located in exon 4. The
frequencies of A and G alleles were 0.069 and 0.931,
respectively. The allelic substitution effect was
significant for milk and protein yield (p < 0.05). The G
allele was unfavorable for milk and protein yield. Genetic
trends for all analyzed traits were significant (p < 0.01)
and that was progressive for milk, fat and protein yield,
but diminishing for fat and protein percent. The effects of
prolactin SNP on genetic trends and the difference between
genetic trends produced by A and G alleles were not
significant for all studied traits.
Key
words:
Holstein,
prolactin, milk, genetic trend, SNP, PCR-RFLP. |
