Despite intensive studies of muscular dystrophy of chicken, the responsible gene has not yet been identified. Our recent studies mapped the genetic locus for abnormal muscle (
AM) of chicken with muscular dystrophy to chromosome 2q using the Kobe University (KU) resource family, and revealed the chromosome region where the
AM gene is located has conserved synteny to human chromosome 8q11-24.3, where the beta-1 syntrophin (
SNTB1), syndecan 2 (
SDC2) and Gem GTPase (
GEM) genes are located. It is reasonable to assume those genes might be candidates for the
AM gene. In this study, we cloned and sequenced the chicken
SNTB1,
SDC2 and
GEM genes, and identified sequence polymorphisms between parents of the resource family. The polymorphisms were genotyped to place these genes on the chicken linkage map. The
AM gene of chromosome 2q was mapped 130 cM from the distal end, and closely linked to calbindin 1 (
CALB1).
SNTB1 and
SDC2 genes were mapped 88.5 cM distal and 27.6 cM distal from the
AM gene, while the
GEM gene was mapped 18.5 cM distal from the
AM gene and 9.1 cM proximal from
SDC2. Orthologues of
SNTB1,
SDC2 and
GEM were syntenic to human chromosome 8q.
SNTB1,
SDC2 and
GEM did not correspond to the
AM gene locus, suggesting it is unlikely they are related to chicken muscular dystrophy. However, this result also suggests that the genes located in the proximal region of the
CALB1 gene on human chromosome 8q are possible candidates for this disease.
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