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41 Cards in this Set
- Front
- Back
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Ex of Single gene effects on behaviour |
Hygienic vs Non-hygienic honey bees -Hygienic colonies remove larvae affected with American Foul Brood |
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Single gene effects are... |
Rare but easy to study: -Behaviours that drop off after cross-breeding are due to single gene effects |
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Types of transgenics |
Knockout - gene removed or rendered inactive Knockin - a novel gene is inserted Conditional - the promoter for a gene is altered so that it can be switched on or off by experimenter |
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Polygenic effects |
Phenotypic characters that are not associated with a specific gene, but are the result of numerous genes interacting |
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Polygenic effects do not... |
Follow Mendalian laws of inheritance |
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Pleiotropy |
Allele has more than one effect on the phenotype |
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Classical Ex of pleiotropy |
Yellow allele in Drosophila -slower at mating -yellow stripes on body *Associative effects |
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Ex of pleiotropy in cats |
40% of white haired, blue eyed cats are deaf -Gene affects pigmentation and hearing |
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How does pigment affect hearing? |
Mice that lack pigmentation, also lack ear canal fluid, and ear canals collapse leading to degeneration of auditory nerves, leading to deafness |
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Approaches to demonstrate genetic effects on behaviour, involving behavioural variation to genetic differences.. |
1. Using natural behavioural variation 2. Using selective breeding 3. Using strain differences |
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Using natural behavioural variation |
Interbreed closely related species with different patterns of behaviour to study genetic influences of behaviour |
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Ex of using natural behavioural variation |
Nest-building behaviour in lovebirds -One carries material in beak, other in tail feather -Hybrid: collects material in beak but looks at and plays with fail feathers **Truly genetic component of behaviour** |
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Selective breeding |
Separate behavioural variants from within a population and select specific individuals *Doesn't work without a genetic component |
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Natural individual variation examples |
Angus are more temperamental than Herefords Brahman cross more agitated during restraint than shorthorns |
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Domestication definition |
Process by which a population of animals become adapted to man and the captive environment by genetic changes occurring over generations and environmentally-induced developmental events reoccurring during each generation |
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Genetic mechanisms influencing domestication |
Inbreeding Genetic Drift Selection |
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Types of selection |
Artificial Natural Relaxation of natural selection |
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Inbreeding creates |
Random changes in gene frequency in small captive populations resulting in genetic variability |
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Inbreeding depression |
Lowering of fitness or vigor due to inbreeding Increased risk of genetic disease |
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Examples of things that will be lowered due to inbreeding depression |
Egg hatchability Clutch size Milk yield Litter size |
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Genetic Drift |
Certain alleles that become randomly fixed or lost |
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Genetic drift results in |
Decreased genetic variability |
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Founder effect |
When a population is bred from a few originators, genetic drift can be exceedingly severe, and alleles from one or two founders can dominate the resulting population |
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What may be a common component of genetic diseases in inbred populations? |
Founder effect |
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The founder effect is a known cause of... |
Behavioural problems in show dogs *Cheetahs |
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Relaxation of natural selection |
Certain behaviours important for survival in the wild lose much of their adaptive significance in captivity |
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Ex of relaxation of natural selection |
Food neophobia, dogs inferior to wolves in observational learning, maternal protective behaviour in poultry |
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Side effects of selection |
Behavioural problems Physiological problems Immunological problems Production diseases |
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Production diseases definition |
Diseases caused by systems of management, feeding and breeding of high producing strains of animals |
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Dairy cattle.... |
Selection to increase milk production -lower energy balance -higher metabolic disorders -more days open -longer calving interval -more services per conception -more digestive problems -more leg injuries (Ca put into milk, not bones) |
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Problem of pleiotropy |
Over-selection for desired traits can lead to pleiotropic selection for undesired traits |
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Ex of pleiotropic problem |
Broiler chickens have been intensively selected for breast muscle mass growth and muscle:carcass weight ratio -altered feeding behaviour -altered weight distribution affects gait -growth of skeleton and internal organs does not keep up |
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Another ex of a pleiotropic problem |
Turkeys who can not mate naturally anymore -reduced cardiopulmonary capacity -can't withstand physical exertion -bone weakness |
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Ex of associative behaviour (pleiotropy and selection environment) |
Selection of rapid growth of individuals can also lead to selection for aggression (so severe, that it could hinder average growth) |
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Genomics is a way of... |
Selecting traits |
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Some genomic receptor studies |
SNPs in genes mediating HPA axis affects vasopressin receptor 1B and glucocorticoid receptors |
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Future directions for genes and behaviours |
Gene editing and Molecular biology |
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2 major hypotheses of dog domestication |
Adoption hypothesis Easy pickings hypothesis |
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Adoption hypothesis |
Humans made it happen through selection of tamest wolves -Bringing home wolf pups and raising them |
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Easy pickings hypothesis |
Food scraps left around human areas Tamer wolves got more scraps and therefore got more food and that supported reproduction |
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Russian domestication experiment |
Chose only the tamest foxes for breeding -By 10th generation, different coat colour, floppy ears, barking and change in tails -Lower adrenaline levels (adrenaline on the same biological pathway as melanin) |
