[Relationship between polymorphism of growth hormone gene and production traits in goats]

Growth hormone (GH) plays an important role in animal growth and development, and the growth hormone gene can be considered as a candidate gene for studying the weight in goats. The function of GH gene has been intensively studied in cattle and pigs, while in goats the study is still rare. In this paper 224 goats including LuBei White goat, Boer goat, hybrid generation 1 and backcross generation 1 of Boer goat and LuBei White goat were used. Two pairs of primers for 5' region of GH gene were designed according to the database of goat genomic sequence (Accession No. D00476) and polymorphisms were detected by PCR-SSCP. Homozygotes of the polymorphic fragment were cloned and sequenced. The result showed that there were five substitution mutations in the two fragments. Statistical analysis showed that in the fragment amplified by the first pair of primers, AA genotype had significant higher birth weight and weight of one year old than BB and AB genotypes in Boer goats (P<0.05). In hybrid generation 1 AA genotype also had higher birth weight and weight of one year old in significantly. While in LuBei White goats BB genotype had lower weight and the weaning weight was significant lower than the other two genotypes (P<0.05). In the fragment amplified by the second pair of primers there was no significant difference among different genotypes. From these results we can preliminarily draw the conclusion that GH gene may be a major gene or linked to the major gene to affect the weight traits and the polymorphic site could be used to select the goat weight in marker-assisted selection program.