Download Behavioral Genetics

Featured Research
Behavioral differences between wild
type and mutant-type fruit flies
• Research question: Why aren’t yellow forms of
fruit flies more common in nature? (Bastock
1956)
• Wild type
– Typical form of an organism or gene that occurs in
nature
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Behavioral differences between wildtype and mutant-type fruit flies
• Methods:
– Fruit flies (Drosophila
melanogaster)
– Interbred wild type
and mutant “yellow”
flies to create inbred
flies
– Conducted mating
trials
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Behavioral differences between wildtype and mutant-type fruit flies
• Results:
– Wild type males had higher mating success than
mutant yellow males
• Conclusion:
– Differences in courtship behavior result in reduced
mating success of yellow individuals
– Variation in genotype associated with variation in
behavioral phenotype
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Fire ant genotype and social organization
• Research question: Do
genes affect variation in
social behavior in fire
ants? (Ross 1997)
• Social organization
– Monogyne – single
reproductive queen
– Polygyne – multiple
reproductive queens
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Fire ant genotype and social organization
• Methods:
– Fire ants (Solenopsis invicta)
– Collected monogyne and polygyne colonies
– Conducted starch gel electrophoresis to compare
allele frequencies at several loci
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Fire ant genotype and social organization
• Results:
– Genotype and allelic frequency at one locus, Gp-9,
differed between two types of colonies
– Monogyne colonies all displayed Gp-9BB
– Polygyne colonies displayed Gp-9Bb
• Conclusion:
– Alleles at one locus appear to regulate social
organization in fire ants
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Figure 11-34
Featured Research
Anxiety-related behavior and knockout
of a hormone receptor in mice
• Research question: What is the function of the
AVPR1A receptor in mice? (Bielsky et al. 2004)
• Arginine vasopressin (AVP) is a peptide
hormone and can affect behavior under
stressful conditions
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Anxiety-related behavior
and knockout of a
hormone receptor in mice
• Results:
– Knockout mice spent more
time in the open, light areas
than did wild-type mice
• Conclusion:
– V1aR gene plays an
important role in affecting
behavior when animals are
placed in stressful situations
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
4.2 The environment influences gene
expression and behavior
• Heritability (h2)
– Proportion of phenotypic variation in a population
due to genetic variation
VG
h 
VP
2
– Broad-sense heritability
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Heritability
• The genetic effects on a phenotype:
1. Additive effects, A, or the average effect of
individual alleles on the phenotype
2. Dominance effects, D, or the interaction
between alleles at one locus
3. Epistasis, I, or the interaction between genes at
different loci
h 
2
VAVD VI
VP
• Narrow-sense heritability
VA
h 
VP
2
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Figure 9-15
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in fruit flies
• Research question: How might differences in
the social environment affect behavior? (Ellis &
Carney 2011)
• Gene expression
– Process by which gene products are formed
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in fruit flies
• Methods:
– Fruit flies (Drosophila melanogaster)
– Treatments:
• Allowed to court a single female
• Interacted with a rival male for 20 minutes
– Controls did not interact with another fly
– Microarray analysis of individuals
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in fruit flies
• Results:
– Identified 240 genes that were responsive only to the
male-male interaction treatment
– Only 16 genes were uniquely responsive to malefemale interaction
• Conclusion:
– Identified 16 candidate genes associated only with male
courtship behavior, while hundreds of other genes
were involved in male-male interactions
– Environmental conditions strongly affect gene
expression and resulting behavior in male flies
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Social environment and birdsong
development
• Closed-ended learners
– Individuals must hear a tutor sing its conspecific
song shortly after hatching in order to learn the
song correctly
• Open-ended learners
– Individuals can acquire new song elements
throughout life
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in birds
• Research question:
What is the role of the
FoxP2 gene in song
development? (Haesler
et al. 2007)
• Song system
– Area of avian brain that
controls song
production
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in birds
• Methods:
– Zebra finches (Taeniopygia guttata)
– Knockdown technique – used a
virus to insert short sections of
RNA into FoxP2 gene to reduce its
expression
– Controls had short sections of RNA
placed in a noncoding region of
DNA
– Adult male tutors and young juvenile
males housed together
– Recorded songs
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in birds
• Spectrogram
(sonogram)
– Allows
researchers to
characterize
acoustic
structure of
vocalizations
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in birds
• Results:
– Knockdown
birds had much
lower FoxP2
expression
than controls
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Social environment and gene
expression in birds
• Results:
– Knockdown birds
tended to omit
specific syllables in
their songs
• Conclusion:
– FoxP2 is required
for normal song
development
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Rover and sitter foraging behavior in
fruit flies
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press
Featured Research
Rover and sitter foraging behavior in
fruit flies
• Results:
– Fed rovers had
much higher foodleaving scores than
did food-deprived
rovers
– No difference
between fed and
food-deprived
sitters
From Nordell and Valone, Animal Behavior: Concepts, Methods, and Applications, © 2014 by Oxford University Press