05-12-2010, 07:43 AM
A group ofgeneticists have tried to map the gene for
severe pediatric gastroesophageal reflux (GER),an
inherited condition characterized by retrograde move-
ment ofstomach contents into the esophagus.In a
study ofthree large families with this disease,the gene
was initially localized to chromosome 13.An array of
microsatellite markers on chromosome 13 was tested
for linkage to the GER gene,and the LOD scores are dis-
played in the table below
Marker--------Recombination fraction
S1------------- -0.36
S2-----4.26
S3-----2.29
S4----- -3.67
S5----- 3.26
Using conventional cutoffpoints for LOD scores,which
ofthe following markers show(s) significant linkage
with the gene involved in pediatric GER?
(A)S2
(B)S2 and S5
©S2,S5,and S3
(D)S4
(E)S4 and S1
severe pediatric gastroesophageal reflux (GER),an
inherited condition characterized by retrograde move-
ment ofstomach contents into the esophagus.In a
study ofthree large families with this disease,the gene
was initially localized to chromosome 13.An array of
microsatellite markers on chromosome 13 was tested
for linkage to the GER gene,and the LOD scores are dis-
played in the table below
Marker--------Recombination fraction
S1------------- -0.36
S2-----4.26
S3-----2.29
S4----- -3.67
S5----- 3.26
Using conventional cutoffpoints for LOD scores,which
ofthe following markers show(s) significant linkage
with the gene involved in pediatric GER?
(A)S2
(B)S2 and S5
©S2,S5,and S3
(D)S4
(E)S4 and S1