Genes and Behavior

1
Genes and Behavior
2
Nature vs Nurture

• Nature
• Genetic component
• Nurture
• Environmental

3
Nature

• Genetic constraints on development of recognition
• Sensitive period of exposure to model
• Learning triggered by specific stimuli (ex.
  Movement or sound)
• Learning is rapid and long lasting
• Learning is apparently irreversible
• http//www.youtube.com/watch?v1yGFrV88t1cfeature
  related

4
Nature vs NurtureThe story of a White crowned
sparrow
5
Whats a dialect?

• A regional or social variety of a language
  distinguished by pronunciation, grammar, or
  vocabulary

6
The Phenomena
http//researcharchive.calacademy.org/research/bma
mmals/sparrows/sparrows2.html
7
Is it Nature?

• How could we test this?

8
White Crowned Sparrow Song Variation

• Different populations of birds have distinctively
  different song dialects
• Are different dialects caused by different genes?

http//psycnet.apa.org/index.cfm?fabuy.optionToBu
yid2001-01020-008
9
Is it Nurture?

• White Crowned sparrows were placed in a chamber
  isolated from sounds
• Isolated birds were unable to produce a complete
  song, only twitters
• Conclusion- a critical environmental factor was
  missing

10
Next Stage of Birdie Torture

• White Crowned sparrows were placed in a chamber
  and adult song played to them
• Birds closely mimicked song that was played to
  them
• Berkeley bird would sing San Francisco song
• What does this tell us about bird song dialects?

11

• Hearing bird song of same species stimulates gene
  expression in brain
• Proteins synthesized modify the functions of
  brain cells
• Alters birds ability to remember song

12
(No Transcript)
13
Nucleic acids

• Information storage molecules
• Directions for building proteins
• Found in nuclei of eukaryotes
• Two forms
• Deoxyribonucleic acid
• Ribonucleic acid
• Polymers of nucleotides

14
Nucleotides

• Nucleotides are the building blocks of nucleic
  acids
• Nitrogenous base
• Adenine
• Guanine
• Cytosine
• Thymine (DNA only)
• Uracil (RNA only)

15
Information stored in Sequence of Nucleotides
16
DNA

• Located in the nucleus of cells
• Has the capacity to store genetic information
• Instructions for all life and life processes
• Contains protein building instructions
• blueprint of life
• Can be copied and passed from generation to
  generation
• Uses specific code built into sequence of
  nucleotides

17
DNA Replication is Semiconservative
18
Chromatin vs Chromosomes
19
Genetic code

• Genes have nucleotide code for building proteins
• Proteins are made of amino acids
• The set of rules giving the correspondence
  between nucleotides of nucleic acids and amino
  acids of proteins

20
Genes Located on Chromosomes

• Gene
• Sequence of nucleotides that is the unit of
  hereditary information
• Ie. A recipe
• Genome
• The sum of an individuals genes

21
Gene Expression

• How dnas instructions are carried out
• Code in gene is copied and used to build
  proteins or run other jobs
• Involves multiple steps
• transcription
• translation
• Uses dna and rna

22
In animal and plant Cells DNA is Isolated in
the Nucleus
Protein Building Structures in cytoplasm
23
Transcription vs translation

• Transcription
• Translation

• Transcription occurs in the nucleus
• Translation occurs in the cytoplasm

• This is how genes control the structures and
  activities of cells

24
Transcription

• Converts Dna to rna
• Results in strand of messenger rna (template)
• Uses Complementary base pair rule
• Region of copying unwinds then rewinds after
  mrna is complete

25
(No Transcript)
26
Messenger RNA (mRNA)

• RNA Template of DNA
• Single strand of nucleotides
• Moves from inside nucleus to cytoplasm

27
Translation

• Converts from nucleic acid (nucleotide) language
  to the protein language (amino acid)
• Converts mRNA to protein

28
Ribosomes Help build proteins
29
Protein Builds your Body
30
Protein Runs your BodyProteins Can Change Cell
Functions
31
Changes in Cell Activity Can Lead to Changes in
Behavior
32
Honey Bee Caste
33
Queen

• Reproductive female
• Lays eggs

34
Workers

• Maintain hive
• Sterile with un-functional gonads
• Care of larvae hatched from Queens eggs
• Nurse workers
• Construct honeycomb
• Regulate hives temperature
• Defense of colony from predators and parasites
• Collection of pollen and nectar

35
Development of Workers Role

• Begins as a honeycomb cleaner after hatching
• Nurse bee- feeds honey to larvae
• Distributes food to workers
• Forages for pollen and nectar outside the hive
• (approx 3 weeks)
• What regulates this change in behaviors?

36
Variation in Gene Expression Influences Behavior

• Comparison of gene activity from nurse and worker
  bees
• 2000 genes change their activity within the first
  4 days of a bees life
• Comparison of 4 day old bees and 8 day old bees
  showed 600 additional genes exhibited altered
  activity
• Differences in gene activity contribute to
  developmental changes occurring in brains of the
  bees

37
Social Environment Influences Gene Expression

• Presence of older foragers inhibits young from
  maturing into foragers
• Transfer of chemicals (ethyl oleate) from
  foragers when regurgitating nectar to nurses
  inhibits transition into forager

38
Gene Expression is a Complex Process

• It is not solely dependent on whether a gene is
  active or not
• Genes and the environment have a complex
  interaction in driving phenotypes and behavior

39

• The one geneone protein hypothesis states that
  the function of an individual gene is to dictate
  the production of a specific protein

40
Genes are made of Introns exons

• Exons
• Segments of DNA that code for AA
• Introns
• Sections of nucleotides that do not code for AA
• Regulatory function

41
mRNA Is Processed

• mRNA processing can influence gene expression
• MRNA is spliced (cut paste)
• Introns removed
• MRNA ends are capped

42
mRNA Is Spliced
43
Rna processing
44
(No Transcript)
45
mRna splicing is an example of Epigenetics

• Wait, whats epigenetics?

46
Epigenetics

• The study of changes in phenotype caused by
  mechanisms that influence gene expression without
  effecting the underlying genes
• Results as a consequence of DNA methylation or
  histone acetylation
• Suppress gene expression without altering the
  silenced genes

47
(No Transcript)
48
Factors that influence Epigenome

• Development in utero
• Environmental chemicals
• Drugs/ pharmaceuticals
• Aging
• Diet

49
Consequences of Epigenetics

• Mechanism to cause changes in phenotype or
  behavior independent of genotype
• Can result in changes of phenotype
• Can result in changes in behavior
• Can result in health effects

50
Epigenome can be inherited

• Methylated regions of DNA are copied when a cell
  replicates
• Cell memory
• Parents may contribute their epigenome to
  offspring

51
Epigenetics Influenced by Diet

• Compounds in food sources are extracted by the
  body
• Compounds are modified metabolically to build
  molecules necessary for building and running the
  body
• Some of these molecules are used to make
  epigenetic tags that interact with DNA to silence
  genes
• Ex. Methyl groups

52
Epigenetics and Diet

• Honey bees
• Complex social groups made up of
• 1 Queen, workers, drones
• Queen is the only reproductive individual
• Reproduction is asexual so all other members of
  the hive are identical clones
• How does phenotypic behavioral variation occur?

53
Epigenetics and Diet

• Royal jelly
• Protein rich substance secreted by pharyngeal
  glands of worker bee
• Larva destined to become a queen is fed large
  quantities of royal jelly by worker bees (nurse)

54
Epigenetics and Diet

• Royal jelly diet interacts with genes
• Royalactin
• Royal jelly silences Dnmt3 gene
• Dnmt3 gene codes for a protein involved in
  genome-wide gene silencing
• When Dnmt3 is active it silences genes in bee
  larva and inhibits them from developing into a
  queen
• Royal Jelly consumed by queen be inactivates the
  Dnmt3 gene so genes can remain active and result
  in queen characteristics
• Effects morphology, physiology, life span and
  behavior

55
Allows Queen Morphology to Develop

• Queen develops functional ovaries and a larger
  abdomen for laying egg

56
Allows Queen Behavior to Develop

• Queen behaviors
• Egg laying behaviors
• Kills rival queens
• Produce communication sounds
• piping
• http//www.youtube.com/watch?v8BWaNwsq3mQfeature
  related
• Pheromone production
• Mandibular gland
• Influences gene expression in worker bee brains
• Mating flights
• Mates with drones from another colony
• Average 12

57
Epigenetics and DietWhat happens if your diet is
poor in
58
In adults changes are reversible

• Switching to a diet rich in methyl donating
  molecules can promote Methylation of genome

59
Epigenetics and Embryonic Development

• Mothers diets deficient in methyl-donating folate
  or choline during late fetal or early post natal
  causes portions of genome to be under-methylated
  for life

60
Epigenetics and Embryonic Development

• Unmethylated agouti gene results in a yellow
  coat. Prone to disease.
• Methylated gene results in brown color and low
  risk of disease

61
Toxin Exposure and Epigenome

• Bisphenol A (BPA) is a compound used in making
  polycarbonate plastic (ex. Water bottle and tin
  cans)
• Exposed yellow agouti mothers produced more
  unhealthy offspring than normal
• Methyl rich diet helped counteract negative
  effects of exposure

62
Center for Disease Control

• BPAs toxic effects in lab experiments are on
  rise
• Compare to rates of same diseases in humans (left)

63
Epigenetics of twins

• http//www.pbs.org/wgbh/nova/body/epigenetics.html
  

64
Sources

• http//learn.genetics.utah.edu/content/epigenetics
  /nutrition/
• http//www.genomeweb.com/dna-methylation-involved-
  epigenetics-crown-queen-bee