In a developing country like Pakistan, livestock sector has a significant importance.
Meat is an important food component in human diet and its source varies from different
organisms like cattle, buffalo, camel, deer, sheep, goat, rabbit and chicken etc. Small
ruminants especially sheep, has a unique role in meat production, due to its feeding and
adaptive behavior. The myostatin (MSTN) gene is known as a candidate gene for
development and growth of livestock because it plays its major role in muscle growth.
Selection is an important tool to improve the meat production and thus enhance the economic
conditions of livestock farmers. For this purpose genetically characterization of meat type
animals, especially the indigenous sheep breeds is not common. The variations in the
myostatin gene have been extensively studied and reviewed in small and large ruminants in
the world but it has been scanty studied in sheep breeds of Pakistan. Thalli and Pak-Karakul
are well known sheep breeds present in Punjab, Pakistan. This study aims to characterize the
genetic variation in the myostatin gene in Thalli and Pak-Karakul sheep breeds.
In this research study, twenty adult animals of two different sheep breeds (Thalli and
Pak-Karakul) were selected from Small Ruminants Research and development Centre, Rakh
Khairewala, District Layyah, Pakistan. Five mL blood sample was collected from each
animal in a 15mL falcon tube containing anticoagulant. Primers were designed by using
Primerfox online software. Primers were optimized using specific protocol and PCR was
performed. DNA was extracted using modified inorganic method of Sambrook et al. (1989).
PCR was carried out using all primers and later sent for sequencing to 1stBase Laboratories,
Singapore. Molecular analysis was done using CodonCode Aligner and MEGA6 softwares.
Ten samples of each breed were sequenced to detect polymorphism in both Thalli and
Pak-Karakul sheep populations. Sequencing revealed G↓T transition at 3995 position in
Summary
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genome (accession number, DQ530260.1) in Thalli and similar transition in Pak-Karakul at
the same position. In Thalli sheep 50 % of experimental animals were heterozygous, higher
level of heterozygosity makes it a potential candidate for higher growth rates. On the other
hand the Pak-Karakul sheep is medium weight breed and frequency of mutant allele was 0.2
or 20%. The observed heterozygous individuals were also with higher live body weights. The
gene frequency shows that this breed has medium potential for its body growth. The
information‟s so generated and further association studies in both breeds will be helpful in
devising breeding plans for increasing mutton production at national level.