Genetic
cline in salinity tolerance of Mytilus
edulis mussels
Leucine Amino Peptidase (LAP) is an enzyme
that cleaves peptide bonds adjacent to Leucine residues
in proteins. In the Blue
Mussel (Mytilus edulis), the
electrophoretic allele lap94
at the leucine amino peptidase (lap)
locus produces a form of the enzyme that has
been shown experimentally to function best in saline
environments. In Long Island Sound east of New York City,
there is a strong salinity gradient beginning with
freshwater in more westerly locations through increasingly
brackish sites eastward (sites 1
8), where salinity
reaches nearly the same level as that on the sea-ward side
of Long Island (sites 9
11). The frequency of lap94 increases
in a cline as a
function of local adaptation to local salinity and
gene flow between adjacent locations. As with other
biochemical adaptations, differences among alleles at the
same locus produce different genotypes, which are expressed
as different phenotypes that are variably adaptive in
different environments.
Homework: In no more than three sentences, define the differences between the enzyme LAP, the gene locus lap, and the allele lap94 . Is the allele lap94 part of the genotype or the phenotype?
8), where salinity
reaches nearly the same level as that on the sea-ward side
of Long Island (sites 9
11). The frequency of lap94 increases
in a cline as a
function of local adaptation to local salinity and
gene flow between adjacent locations. As with other
biochemical adaptations, differences among alleles at the
same locus produce different genotypes, which are expressed
as different phenotypes that are variably adaptive in
different environments.Homework: In no more than three sentences, define the differences between the enzyme LAP, the gene locus lap, and the allele lap94 . Is the allele lap94 part of the genotype or the phenotype?