ANSC 363 Exam 1 Notes

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University of Illinois, Urbana Champaign *

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363

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Anthropology

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Oct 30, 2023

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Principles of natural selection: 1) Trait variation: members of same species may differ in their characteristic 2) Heredity: parents may pass off traits to their offspring 3) Differential Reproduction: Due to their special inherited characteristics, some individuals tend to leave more offspring than others Genetic View of Natural Selection: Definition: Process in which individuals with a particular trait tend to leave more offspring in the next generation than others with a different trait 1) Genetic Variation: genes can occur in 2 or more forms (allele) 2) Heredity: by definition, alleles can be transmitted from parent to offspring 3) Differential Reproduction: alleles that contribute to the development of traits linked to individual reproductive success will become more common overtime. Adaptation as a process: (As a process)—Evolution of a population by natural selection in which hereditary variants most favorable to organismal survival and reproduction are accumulated and less advantageous forms discarded. *Character Adaptation—A character that evolved gradually by natural selection for a particular biological role. **ANIMAL BEHAVIOR IS A SUBJECT OF NATURAL SELECTION. **We must understand wild species behavior to better understand domestic species. **Domesticated behavior in dogs is inherited. DOMESTIC ANIMALS ARE FUNCTIONING IN A VERY SIMILAR WAY TO THEIR WILD RELATIVES!!! (marking territory by urinating on trees, bury bones, roll on degrading deer skins—examples of dogs displaying their wild relatives behaviors) Genetics of adaptation of Peromyscus Mice (Know the name of gene and effects of different alleles on coat color) ● Melanocortin receptor 1 gene (Mc1r) causes different coat colors ○ Codes for the version of protein that causes mice to have light color or dark color ○ Two alleles differ by one nucleotide (Arginine to Cysteine) ○ Mutation of Mc1r is beneficial in the right environment (light colored for beaches) - P. Polionotus: Open-fielded specialist restricted to Southeast U.S - Long entrance tunnels, ingenious escape tunnel

- Build tunnels of same length and shape (consistent) - P. Maniculatus: Generalist that inhabits prairies and forests - Short entrance tunnel, no escape tunnel ● Suggested that burrowing behavior is genetically controlled ● TEST: Crossed a hybrid polionotus and maniculatus ○ Polionotus allele is dominant ● Lots of variation in backcross burrows ○ Backcrossed mice (mixed) that built polionotus burrows carry the genome from polionotus ● QTL mapping: used to find the burrowing genome ● Tunnel length and escape tunnel length = weakly correlated ○ Simple behavior + simple behavior = complex behavior ● 3 genomic reasons responsible for tunnel length and 1 genomic region for escape tunnel length ○ CONCLUSION: Burrowing is governed by 4 genomic region. Natural vs artificial selection - Natural Selection: Individuals with a particular trait tend to leave more offspring in the next generation than others with a different trait - Artificial Selection: Intentional breeding of an individual, usually applied after domestication takes place. It is used to maintain certain qualities of an individual. Humans choose which individuals will reproduce ● Artificial selection is applied BEFORE REPRODUCTION and natural selection is measured AFTER REPRODUCTION Why are domesticated animals not simple tamed animals? - Domestication is a process which involves animal transformation through many generation. Differences include: behavior, physiology, morphology, appearance, reproduction, nutrition - Domestication shows: reduced aggressiveness and sensitivity to environmental changes and increase social tolerance among conspecifics. Time Scale of Animal Domestication (need to know current view on the time and geographical locations of domestication for such species as dog, cat, pigeon, horse, sheep, goat, pig, cattle, and humped cattle). You also need to know names of ancestral species of these domesticated species.

1) Dogs (~15,000 BP) a) Geographic location (debated issue): East or Central Asia (Near East generally) b) Number of Domestication Event: debated - ~400 dog breeds recognized (breed registration started ~200 years ago - Selection and breed focused on Morphology and Appearance 2) Cats (7,500 BP in Cyprus, 3,500 China, 1,550 Egypt) a) Ancestral species: wild cat, Felis silvestris - Value: pest controllers - Modern cats: first to show in London 1871 - International Cat association accepts 57 breeds ( 41 in U.S) 3) Cows ( 8000 for Taurus, 5000 for Zebu) a) Ancestral species: Common cattle = Bos taurus taurus | Zebu = bos taurus indicus) i) Both descended from aurochs (wild ox = Bos primigenius) - Division between these two estimated 300,000 - 2 million years ago - Divergence took place before domestication ● Humpless ( bos taurus) cattle: 8000 years ○ Geographical: Europe, north asia, west africa ● Humped ( bos indicus) 5000 BP ○ Geographical: Indus valley 4) Pig ( Sus Scrofa domesticus) 9000 BP Near east a) Ancestor: Wild boar (sus scrofa) 5) Sheep ( Ovis Aries) 11,000 BP a) Ancestor: the mouflon (O. Orientalis) and Argali (O. Ammon) - Archeological Data: Fertile Crescent 6) Goat ( Capra aegarus hircus) ~10,500 BP in Anatolia | ~9,500 in Zagros mountains a) Ancestor: bezoar (Capra aegarus) 7) Horse: (Equus ferus caballus) 4-5,000 BP in the botai culture a) Ancestor: wild horse (tarpan, equus ferus) - Perissodactyla = odd-toad ungulate)

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8) Chickens: 8,000 BP Southeast Asia 9) Rock Pigeon ( Columba livia): 3,000-5,000 BP | Food source as early as 10,000 BP - Geographical Location: Mediterranean ● Factors that can prevent domestication (Diamond’s paper) 1) Diet not easily supplied by humans 2) Slow growth rate/long birth spacing 3) Nasty disposition 4) Lack of follow the leader dominance hierarchy 5) Reluctance to breed in captivity 6) Tendency to panic in enclosures or when faced with predators Experimental domestication + Fox Domestication Experiment) 1959 - present (Dr. Dmitry and Dr. Lyudmila Goal: reconstruct domesticated animals Hypothesis: Selection for behavior was main driving force of dog domestication Outcome: selection for friendly response to humans leads to other changes in behavior, physiology, development and appearance - Selection for wild rats (Rattus norvegicus) for behavior - Started in Institute of Cytology and Genetics in Novosibirsk 1972 - 233 wild-caught rats used for selection - Changes in Physiology and Appearance - Decreased anxiety in tamed rats - Lower level of corticosterone in tamed rats - Increase frequency of white spotting in tame population ● What do the results from experiments tell us? - Selection of both fox and rats for friendly behavior led to similar results - Selection for tame behavior led to changes in behavior, physiology, development, and appearance EXAMPLES OF WILD BEHAVIORS (GOOD AND BAD) Of Domestic Species. Why? - Mark territory - Bury bones/toys for future use

- Roll on degrading deer skins - Hunting when food is provided What is “TELEOLOGY”? - Ascribing to animals the capacity to force the end result of their behaviors - Cannot assume animals can anticipate outcome of more innate behaviors - Example: cow licked newborn calf to stimulate it to stand and suckle - Cat licking its wound to prevent infection - Sheep staying in flock to minimize predation Sources of Behavioral Variation 1) Genetic Variation: Behavioral variation due to differences in individual genotypes at specific genes 2) Environmental Variation: Behavioral traits are exquisitely sensitive to variation in behavior 3) Gene-Environment Interaction (GEI): Can arise if specific differences in the environment have greater effect on some genotypes than others. QUANTITATIVE TRAITS (BEHAVIORAL TRAITS) - Continuous behavioral traits: - time length of an exploratory activity - Length of vocalization, variation on exit speed, maze exit time - Height, weight, milk yield - Categorial behavioral trait: Number of barks per minute, # of times calf approaches cow, # of enters to feeding area How can we test that a trait is heritable? How would we set up an artificial selection experiment? - First need to know if trait of interest is heritable - Quantitative vs Qualitative - Create a distribution (sum of larger number of random quantities always converge to normal distribution) - Use line of best fit - Measure Heritability (0 means that the observed variation does not have genetic basis | 1 means that the trait is largely explained by genetics) - Artificial selection means that it’s under human control which doesn’t take into account animal’s fitness

Forward Genetics and Reverse Genetics: 1) Forward : using genetic mapping, can identify genetic architecture of behavioral traits and genes involved in regulation of these behaviors 2) Reverse: Used to help understand the function of a gene by analyzing phenotypic effects of a gene sequence Examples of gene effects on behavior - P. Polionotus and P. Maniculatus: they build different types of burrows - Peach faced lovebirds use rump feathers to stop nesting materials from falling/moving, fishers use beaks ● Brooding Behavior in chickens (females only) - The gene responsible for broodiness is thought to be located on Z chromosome. *White Leghorn females are not broody (ZW) *Cornish females are broody (ZcWc) - Sex-linked trait - Love of broodiness determined by breed of father - NOT in males because it lacks prolactin Lovebird nest building behavior - Peach faced lovebirds use rump feathers to stop stop nesting materials, fishers use beaks Environmental Effects on Behavior - Behavior of genetically identical individuals is not identical due to environment effects - Example: maternal behavior Maternal Effects: - Differences in maternal behavior lead to differences in behavior of their offspring. - Hybridized offspring from parents of 2 distinct population exhibits behavioral differences similar to mothers - Could be hybrid parents traits - Could resemble a dominant gene - Could be worse than parents (inbreeding) - Could be better than both parents - Examples: A cross between cocker spaniels and basenji pups Gene-Environment Interaction - occurs when strains or breeds of animals perform differently, relative to each other in different environments

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- Example: Male chickens reared without females had greater performance scores that those raised with females Rats from "dull" and "bright" strains were raised in three different environments: • i) standard laboratory environment: bright > dull • ii) impoverished environment without bedding material or any stimuli: both poor • Enriched environment: both good or equal performance Bar Harbor Experiment (~1950-1963) Goal was to observe differences in trainability - Walk on leash, learning to be quiet on weight platform - Genetically determined differences in behavior of dogs 1) Basenji 2) Beagle 3) Cocker Spaniel 4) Shetland Sheepdog 5) Wire-haired fox - Measuring emotional activity showed big differences ● Terries, beagles, basenjis more emotional than shelties and cockers - Problem solving behavior evaluated in different tests (maze test) ● Terriers and shelties made more errors and took longer ● Basenjis were good the first day of learning ● Beagles overall superior - The Bar Harbor experiment clearly demonstrated genetic component in among breed and within breed variation in behavior. - The results of this experiment had a profound effect not only on our understanding of dog behavior but on other disciplines including human biology.