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Genes and the Environment
AP Biology
Fall 2010
 The
environment contributes to
variations in gene expression amoung
individuals in a population
 Fur
on the extremities of Himalayan
rabbits will be darker
 This is because the enzyme for melanin
production will operate at cooler
temperatures but, is sensitive to heat on
the rest of the body
 Cuttings
(come from the same parent plant)
from Yarrow plant clones grew differently at
three different altitudes
 Cuttings from one plant grew tall at the
lowest and the highest elevation
 But a third cutting remained short at midelevation
 Even though these plants were genetically
identical, their phenotypes differed in
different environments
 The
colour of the floral clusters on
Hydrangea will vary depending on the
acidity of the soil
 Some
people tolerate stress better than
others
 Perhaps due to differences in the gene
for a serotonin transporting protein
 Serotonin compromises response to
stress
 Understand
that environmental factors
can influence gene expression, know
some examples
 How could this be a positive or negative
factor?
 Would this have anything to do with the
nature/nurture debate?