Behavioral Genetics

Question 1

Twins

Answer 1

If genes influence trait —> twins must both exhibit —> increased correlation but not perfect

Question 2

Heredity and verbal ability (Plomin)

Answer 2

Monozygotic (identical) and those adopted together have highest correlation of verbal ability, both genetic and environmental related causes

Question 3

Dilger (1962)

Answer 3

Genetic basis of lovebird behavior (examined hybrids)

A. roseicollis: carries nest material in rump feathers
A. fisheri: carries nest material in bill

Hybrids attempt to carry in rump feathers, but always fall out since not secured preperly

Question 4

Genetics of cricket songs
(Bentley & Hoy, 1972)

Answer 4

forewings specially modified for sound production - “scraper” located on upper surface of lower wing & rubbed against a row of bumps (“file” on underside of upper wing

T. commodus x T. oceanicus hybrids

Maternal effect –> mom influence song of male hybrid offspring –> hybrid female will show preference to similar maternal songs

Question 5

stridulation

Answer 5

rubbing of one body part against another

Question 6

quantitative traits

Answer 6

refers to phenotypes that vary in degree + can be attributed to polygenetic traits and their environment

Question 6

MacLean et al (2019)

Answer 6

“Genotypic variation accounts for around five times more variance in analyses across versus within breeds”

Question 7

Scott & Fuller research on dog behavior (1965)

Answer 7

Chose dog breeds that differ substantially in temperment (cocker, basenji, Shetland sheepdog, wire fox terrier, beagle) –> mom spends most time raising young

Findings:
* heredity affects almost every trait tested
* high complex pathway between primary gene action & final effect on behavior

Question 8

Belyaev (1965)

Answer 8

• Silver fox (species related to dogs but not domesticated) –> researchers feed + pet foxes in various group/individual settings –> breed for tameness –> after 10 generations: floppier ears, curled tails, lighter coats, bark like dogs
• Different hormone levels in new generation: significantly lower adrenaline + melanin

Question 8

Lynch (1980)

Answer 8

Artificial selection for nest building in mice

Differentiate throughout 15 generations

Question 9

Rothenbuhler (1964)

Answer 9

• Some strains of honeybees susceptible to bacterial infection that kills larvae (American foul brood disease - non-hygienic strain)

Proposes 2 loci model to determine inheritance (uu - uncapping; rr - removal)

• Hygienic = uncapping larval cell + removing dead larva from cell
• Hygienic x non-hygienic = non-hygienic phenotype (hygienic = recessive)
• Uurr type unable to remove cap from cell

Question 10

Drosophilia (single gene behavioral mutants)

Answer 10

• Amnesiac (remembers what odors to avoid for a few min –> forgets)
• Dunce
• Stuck (male fails to dismount after normal 20 min of fucking)
• Coitus interruptus (males dismount prematurely)
• TKO (Mechanical jolt –> falls over –> twitches –> comatose for a few min)
• Yellow (males have reduced mating success)

Question 11

Bastock (1956)

Answer 11

• First study revealing single gene difference could affect behavior (yellow male reproductive success)
• Yellow mutation also produces weird ass mating song

Also shows pleiotropy

Question 12

Drosophilia “wings up” mutation

Answer 12

• Microarray analysis - analyze cells from different body parts of wings up fly to find functional site

Question 13

Benzer & Drosophilia gynandromorphs (1972)

Answer 13

• exhibit male and female traits (produced by “ring-shaped” X-chromosome, unstable during first division)
  * W-: recessive mutation
  * W+: wild dominant type
• If lose sex chromosome –> offspring guaranteed to be samegender
• male half: short wing, white eye
• see which is expressed –> connection to sec (wing-up mutation, marker enzyme mutation)

Question 14

Deneris

Answer 14

• “PET-1” removed in mice –> increased aggression as adults
• PET-1 gene active only in brain neurons that produce seratonin

Question 15

Young (Vole mating systems)

Answer 15

* Prarie (monogamous), Montane (promiscuous)

• mating –> choose partner, stranger, neutral
• Montane neutral, Prairie partner
• when monogamous Prairie vole mates, vasopressin released –> pleasure and reward (receptor locations are different for Montane and Prairie)
• Promiscuous voles have fewer receptors in forebrain related to reward and pleasure –> gene insertion for extra V1a receptors –> promiscuous males tend to mate with single female

Question 16

Herb et al (2012)

Answer 16

• Reversible switching between epigenetic states in honeybee behavioral subcastes
• Tasks workerbees perform linked w/ age: cleaning cells –> feeding larvae –> feeding nestmates –> packing pollen –> foraging
• Particular genes expressed @ types
• Researchers able to reverse this pattern based on gene expression

Question 17

Epigenetics

Answer 17

functionally relevant changes to the genome that X involve change in nucleotide sequence

ex. DNA methylation: biochemical process where methyl group added to C or A DNA nucleotides

Question 18

Tryon (1942)

Answer 18

• genetics of rat intelligence - selective breeding experiment
• tested rates for maze running ability & bred for good/poor specific groups
• selection for specific maze performance, not general intelligence