Transcript profiling of expressed  sequence tags from semimembranosus muscle of commercial and  naturalized pig breeds.
In  general, genetic differences across different breeds of pig lead to variation  in mature body size and slaughter age. The Commercial breeds Duroc and Large  White and the local Brazilian breed Piau are ostensibly distinct in terms of growth  and muscularity, commercial breeds are much leaner while local breeds grow much  slower and are fat type pigs. However, the genetic factors that underlie such  distinctions remain unclear. We used expressed sequence tags (ESTs) to  characterize and compare transcript profiles in the semimembranosus muscle of  these pig breeds. Our aim was to identify differences in breed-related gene  expression that might influence growth performance and meat quality. We  constructed three non-normalized cDNA libraries from semimembranosus muscle,  using two samples from each one, of these three breeds; 6902 high-quality ESTs  were obtained. Cluster analysis was performed and these sequences were  clustered into 3670 unique sequences; 24.7% of the sequences were categorized  as contigs and 75.3% of the sequences were singletons. Based on homology  searches against the SwissProt protein database, we were able to assign a  putative protein identity to only 1050 unique sequences. Among these, 58.5%  were full-length protein sequences and 17.2% were pig-specific sequences.  Muscle structural and cytoskeletal proteins, such as actin, and myosin, were  the most abundant transcripts (16.7%) followed by those related to  mitochondrial function (12.9%), and ribosomal proteins (12.4%). Furthermore,  ESTs generated in this study provide a rich source for identification of novel  genes and for the comparative analysis of gene expression patterns in divergent  pig breeds.
Departamento de Zootecnia, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
C S
CS
Nascimento
J O
JO
Peixoto
L L
LL
Verardo
C F
CF
Campos
M M C
MM
Weller
V R
VR
Faria
M E
ME
Botelho
M F
MF
Martins
M A
MA
Machado
F F
FF
Silva
P S
PS
Lopes
S E F
SE
Guimarães
D000818:Animals; D001947:Breeding / Q000191:economics*; D003132:Commerce; D018076:DNA, Complementary / Q000235:genetics; D030562:Databases, Protein; D020224:Expressed Sequence Tags / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism*; D009928:Organ Specificity / Q000235:genetics; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D034421:Sus scrofa / Q000235:genetics*
D018076:DNA, Complementary; D011506:Proteins; D012333:RNA, Messenger