Twins
If genes influence trait —> twins must both exhibit —> increased correlation but not perfect
Heredity and verbal ability (Plomin)
Monozygotic (identical) and those adopted together have highest correlation of verbal ability, both genetic and environmental related causes
Dilger (1962)
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
Genetics of cricket songs
(Bentley & Hoy, 1972)
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
stridulation
rubbing of one body part against another
quantitative traits
refers to phenotypes that vary in degree + can be attributed to polygenetic traits and their environment
MacLean et al (2019)
“Genotypic variation accounts for around five times more variance in analyses across versus within breeds”
Scott & Fuller research on dog behavior (1965)
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
Belyaev (1965)
- 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
Lynch (1980)
Artificial selection for nest building in mice
Differentiate throughout 15 generations
Rothenbuhler (1964)
- 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
Drosophilia (single gene behavioral mutants)
- 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)
Bastock (1956)
- First study revealing single gene difference could affect behavior (yellow male reproductive success)
- Yellow mutation also produces weird ass mating song
Also shows pleiotropy
Drosophilia “wings up” mutation
- Microarray analysis - analyze cells from different body parts of wings up fly to find functional site
Benzer & Drosophilia gynandromorphs (1972)
- 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)
Deneris
- “PET-1” removed in mice –> increased aggression as adults
- PET-1 gene active only in brain neurons that produce seratonin
Young (Vole mating systems)
* 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
Herb et al (2012)
- 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
Epigenetics
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
Tryon (1942)
- 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
