Evolution and Domestication animals

Domestication

What is domestication? 1. "Process of developing a mutually useful relationship between animals & humans" 2. Changing the behaviours & nature of wild animals • - tamer, quieter, accepting of humans & biddable - accentuating traits desired by humans 3. Domesticated species --> evolutionary process has been influenced by humans to meet their needs 4. Typically the product of a breeding population that is genetically isolated from the wild species - reproductive isolation 5. Economic advantage 6. Different animals domesticated at different times & in different parts of the world Domestication criteria: 1. Flexible diet --> easier to feed 2. Reasonable growth rate --> will reach maturity for eating/breeding in a reasonable time 3. Breed in captivity 4. Pleasant disposition --> amenable to human company & interference 5. Steady temperament --> management easier - minimal change with maturity, season etc 6. Modifiable social hierarchy --> will accept humans, can be managed more easily

Evaluation of Cats - 2

1. Analyses of mitochondrial DNA determined that all domestic cats are descended from the Near Eastern wildcat Felis sylvestris lybica: - Near East = Middle East; includes Egypt... - 12,000 years ago 2. Mummified Egyptian cats have a brain size identical to that of Felis s. lybica 3. Correlates with when the first agricultural societies began to flourish in the Fertile Crescent (inc Egypt) 4. Felis s. libyca still found in Middle (Near) East, India, Corsica, Sardinia & Majorca 5. Tawny brown coat, light stripes, ticking 6. Rare, genetically pure cats almost extinct: - identical chromosome numbers & structure to domestic cats 7. One of the earliest & most important changes in cats in Europe was development of tabby patterning - better camouflage in forests 8. More stocky, or cobby, body & head - adaptation to cold 9. Both may have come about as a result of matings with the European wildcat (Felis silvestris silvestris) 10. Long hair is the result of a spontaneous mutation that became fixed through inbreeding in an isolated & cold environment: - likely in Turkey - may also have occurred in Iran & Russia 10. Environmental adaptation through genetic mutation, geographical isolation and, finally, human preference resulted in breeds 11. In the 16th century, Persian (Iranian) cats were transported into Europe 12. Longhaired cats from Russia were brought to England 13. Early longhaired cats in the US appear to be descendents of shorthairs that carried the recessive longhair mutation - brought to the New England colonies in early to mid 1600s - those with long hair better able to withstand the winters 14. Geographic isolation & natural selection resulted in the Maine Coon cat - 'Coon' derived from early belief that they were the result of matings between cats & raccoons

Evolution of birds

1. Birds evolved from small, predatory dinosaurs 2. Fossils (rock & amber): - transition from dino-fuzz to flight feathers - loss of teeth - loss of tail - fusion & modification of skeletal elements 3. Continued to evolve characteristics that are uniquely adapted for flight: - Gradual reduction, loss & fusion of many skeletal elements: vertebrae & bones of the pelvic girdle - Reduction in overall body size - Outer cortex of bones thinner but more dense (greater strength & rigidity) - Bones hollow or have trabeculae (invasion by diverticula of air sacs) - Sternum became larger, & evolved a central keel to anchor the flight muscles - Forelimbs became longer than the hindlimbs, as the main form of locomotion switched from running to flight - Teeth were lost repeatedly in various lineages of early birds

Domestication of Chickens

1. Domestic chicken is Gallus domesticus 2. First domesticated from the red jungle fowl (Gallus gallus): - still runs wild in most of southeast Asia 3. Likely hybridised with the grey jungle fowl (Gallus sonneratii) 4. Domestication occurred around 8,000 years ago 5. Likely for cockfighting, not for eating or eggs 6. Multiple origins of domestication (China, Laos, Burma & India) 7. First archaeological evidence is from China ( around 5,400 BC ) 8. Domesticated chooks in Indus Valley by ~2,000 BC (India, Pakistan, Bangladesh, Nepal, Sri Lanka & Bhutan) 9. From Indus Valley spread into Europe & Africa 10. Domesticated chickens differ from the wild jungle fowl in both behavioural & physiological traits: - less active - have fewer social interactions - less aggressive 11. Increased adult body weight 12. Reach sexual maturity earlier: - egg production starts earlier - more frequent laying - larger eggs 13. Broiler chickens for meat: - Australians love their chook ( ~460 million broilers produced annually (2007)) - reach slaughter weight at ~5-7 weeks of age - reach a weight of ~2kg in 35 days while consuming only 3.2kg of feed - genetic selection ongoing for improved performance & decreased time to reach market weight - rapid growth & selection for enlarged breast muscles (skeletal malformation & dysfunction --> leg deformities) 14. Layer hens: - traditionally Australorp, White Leghorn ( slightly tinted, essentially white eggs) - Australian consumer preference for tinted eggs (imported strains that give brown eggs) (US market almost entirely white eggs) (Specialist market persists in Australia --> Orthodox Easter) - production peaks achieved at ~26 weeks of age - genetic selection aimed at "hen day production" (approaching physiological limits of an egg a day) (sustainability of production of saleable eggs)

Domestication of dogs - 2

1. Human families & societies share many similarities with dog/wolf packs, that would have facilitated domestication: - hierarchical order (communicate status, dominance vs submission) (males physically dominant over females) - work co-operatively - strong kinship ties - suspicious of outsiders - care for & protect young even if not theirs - refined ability to interpret moods 2. Ability of dogs to read human gestures remarkable 3. Even our closest relatives, chimpanzees & bonobos, can't read our gestures as accurately as dogs can 4. Left gaze bias - when humans meet a new face, their eyes shift left to settle on the right side of the face - right side better at expressing emotional state - dogs also display left gaze bias - only when looking at human faces 5. Finger pointing 6. Co-evolution of dogs & humans is embedded in our respective genomes 7. Several groups of genes in humans & dogs — related to diet & digestion, neurological processes & disease — have been evolving in parallel for ~20-40 thousand years 8. Driven by shared environments of humans & dogs 9. Ability to easily digest starch 10. Dogs have multiple copies of a gene for amylase - 4-30 copies - wolves have 2 copies 11. Humans have also undergone amylase gene duplication - invented agriculture & settled into diets rich in grains 12. Extended eye contact between dogs & their humans increases oxytocin levels in both - oxytocin plays an important role in maternal bonding - promotes trust & empathy 13. If humans selected dogs based on behavioural traits, could this affect physical traits? --> Belyaev's experiments in silver foxes (1979) 14. Most foxes aggressive & fearful towards humans - around 10% less so - selectively bred these calmer foxes 15. After 20 generations - actively sought contact with people, lick hands & faces, whine & wag tails 16. Females started breeding twice a year 17. Longer moulting time, drooping ears, erect tails, coat colour changes 18. Retention of juvenile traits

Domestication of dogs - 1

1. Originally thought that dogs (Canis familiaris) evolved from the Eurasian grey wolf (Canis lupus) - Canis lupus familiaris - subspecies of grey wolf 2. Analyses of mitochondrial DNA - sequences of dog & grey wolf differ by 0.2% - sequences of grey wolf & coyote differ by 4% 3. However, recent data (2014, 2015, 2016 & 2017...) indicate that dogs & wolves evolved from a now extinct common wolf ancestor 36,900-41,500 YBP - lower jaw found on Siberia's Taimyr Peninsula - ~9,000 - ~34,000 years ago - genetic overlap observed between some modern dogs & wolves is the result of repeated inter-breeding after dog domestication - extinction of Taimyr wolf ancestor confounds efforts to identify when dogs were domesticated 4. In June 2016, a further study concluded that dogs were domesticated twice - Initial wolf population split into European & Asian populations - Each was separately domesticated between ~20,000- 40,000 yrs ago * dog evolved from wolf 36,900-41,500 yrs ago * dog evolved before it was domesticated (ie dog did not evolve from domesticated wolves) - Original wolf populations became extinct 5. Humans from east Asia migrated to Europe, bringing dogs with them at least 6,400 yrs ago - this happened after European dog populations had reached very low numbers ( modern dog DNA traced back to Asian, not European, dogs) 6. Key point is that dogs were domesticated before humans transitioned to agricultural societies - earliest dogs lived among hunter-gatherer societies & adapted to agricultural life later 7. More complicated history than previously thought - ie early farmers adopted a few docile wolves 8. Dog is the first domesticated species 9. The only large carnivore humans ever domesticated 10. Did humans choose the wolves/dogs or did they choose the humans? - took advantage of carcasses that humans left - over time moved more closely into human niche 11. People who had dogs during a hunt would likely have had an advantage over those who didn't 12. Wolves following the migratory patterns of early humans would have given up their territoriality - would have been less likely to reproduce with resident territorial wolves 13. Analogue of this process today: - migratory population of wolves in North America - follow the caribou migration - when they return from the tundra to the forest during the winter they do not reproduce with resident wolves that don't migrate

Domestication of dogs - 3

1. Sociability around strangers, curiosity, playfulness, liberal tail-wagging & solicitation of attention - traits seen in both wolf pups & dog pups - retained in adult dogs but not wolves 2. Floppy ears, shorter muzzle & broader faces - puppy-like - persist in adult dogs but not wolves 3. Retention of juvenile traits into adulthood - paedomorphosis - key feature of domestication (seen in Belyaev's foxes) (pleiotropy --> one gene affects several traits) 4. Role of neural crest cells? - Some of the phenotypies associated with domestication are similar to those seen in individuals with pathologies in neural crest development (may be source of variation in behaviour, the integument (eg coat colour) and the facial skeleton (shortening of muzzle)) 5. Genome sequencing: Kukekova et al. 2018 - Role of SorCS1 gene - Mutations in humans associated with behavioural disorders - Involved in synapse function 6. Evidence for the appearance of breed variation 7. Medium-sized dogs identified in the Near East (Syria, Israel, Iraq): ~15,500-11,000 years ago 8. Medium to large dogs identified in Germany, Russia & Ukraine: ~17,000-13,000 9. Small dogs identified in Germany, Switzerland, France & Spain: ~15,000-12,300 10. Recent DNA analyses: - despite marked size differentiation in early dogs, has nothing to do with current dog breeds 11. the oldest modern dog breeds are no more than 500 years old, most date only from ~150 years ago

Evaluation of Cats - 3

1. The Manx is an example of one of the earliest spontaneous mutations - appeared on the Isle of Man & existed in isolation for centuries 2. By the mid 1800's the English were starting to 'collect' exotic cats from around the world, brought back to England from trade & colonisation routes - so began the selective breeding & showing of cats 3. World's first cat show in London in 1871 - not everyone was appreciative of the new breeds on display ( "an unnatural, nightmare kind of cat" --> sealpoint Siamese) 4. British began to refine & develop most of the breeds that were subsequently exported all over the world 5. There are currently 43 registered breeds 6. There are 2 difficulties inherent in determining when & how the cat was domesticated: - Domesticated cats can, & do, interbreed with their wild cousins * Bengal (hybrid of domestic cat x asian leopard cat (Prionailurus bengalensis)) - A primary indicator of domestication is sociability... 7. Why were cats domesticated? - cats appear to contribute little... 8. Near East around 12,000 years ago - when the first agricultural societies began to flourish in the Fertile Crescent (Lebanon, Syria, Iraq, Israel, Jordan & Egypt) 9. Wild cats attracted to human settlements by the mice & rats who came to feed on agricultural stores 10. Cats domesticated themselves 11. Domestic cats identified archaeologically - relatively small size compared to feral cats - presence outside of their normal range - burials, collars, adornments 12. Long believed that the ancient Egyptians were the first to domesticate cats (3,600 years ago) - recent genetic & archaeological data refute this 13. The oldest archaeological evidence found in Cyprus - neolithic site of Shillourokambos - cat burial next to a human burial - 9500-9200 years ago

Evolution of dogs

1. The dogs' closest relative is the grey wolf (Canis lupus) 2. Dog & grey wolf are sister taxa - both evolved from a common ancestral wolf 3.Wolves belong to the Order Carnivora - over 260 species, including dogs, cats, bears, foxes & seals... 4. Within the Order Carnivora is the Family Canidae - wolves, domestic dogs, foxes, coyotes & dingoes 5. Around 60 million years ago, small, weasel-like mammal - genus Miacis - ancestor of the Canidae - Nth America 6. 30-40 million years ago, Miacis had evolved into the first true dog-like mammal, Cynodictis - Greek for "in-between dog" - elongation of the limbs & feet --> running - carnassial teeth specialised for shearing --> meat - expanded cranium (& brain) --> intelligence 7. Evolution of dogs (& their wolf ancestor) is characterised by the acquisition of these 3 traits 8. Cynodictis gave rise to 2 branches: Africa & Eurasia • Eurasian branch: Tomarctus - progenitor of wolves, dogs & foxes 9. Thereafter, the evolution of dogs is tightly connected to their domestication - Diverged from wolf ancestor ~40,000 yrs ago - Likely driven by presence of humans

Evaluation of Cats - 4

1. The first illustration of a cat with a collar appears on an Egyptian tomb in Saqqara - Old Kingdom, 2500-2350 BC 2. Middle Kingdom, 1976-1793 BC - frequently in statuary & paintings - mummified (most frequently mummified animal) (cat cemetery in Beni-Hassan 300,000 mummies) 3. New Kingdom, ~1000 BC, worshipped as deities - Mafdet, Mehit & Bastet - killing a cat meant a death sentence 4. Phoenician traders (1500-300 BC) exported cats from Egypt to the British Isles in exchange for tin 5. Ancient Romans also held a reverence for cats - symbol of liberty - smuggled out of Egypt 6. In Japan, cats introduced around 6th century BC - protection of treasured manuscripts in temples from rodent attack - 2 cats in each temple 7. In Europe during the Middle Ages (5th-15th Centuries), cats (especially black) were demonised - nocturnal & so roaming at night = malevolent 8. Pope Gregory IX (1227-1241) published Vox in Rama - black cats are the incarnation of Satan - killed in an effort to ward off evil - helped to spread the bubonic plague (rats) 9. 1600s public image of cats began to improve

Evaluation of Cats - 1

1. Within the Order Carnivora is the Family Felidae 2. Felids are the strictest carnivores of the Carnivora 3. Extant felids belong to one of two subfamilies: - Pantherinae: tiger, lion, jaguar & leopard - Felinae: cougar, cheetah, serval, lynxes, caracal, ocelot & the domestic cat 4. Earliest known Felid is Proailurus: - late Oligocene & early Miocene - ~25 million years ago - Eurasia - binocular vision - highly specialised carnassial teeth for shearing meat - retractable claws - completely carnivorous 5. During the Miocene, it gave way to Pseudaelurus 6. Pseudaelurus: - Eurasia, Africa & North America - 8-20 million years ago - Skeletons very similar to those of extant 'big cats' - Common ancestor of the two extant subfamilies (Pantherinae & Felinae) - And the extinct subfamily Machairodontinae: ( saber-tooth cats) (extinct in the Late Pleistocene (~12,000 yrs ago)) (3 genera: Smilodon, Machairodus & Homotherium) 7. Approximately 60% of the modern felids are estimated to have developed within the last million years 8. Wild felids are native to every continent except Australia & Antarctica 9. Felids share a genetic anomaly that prevents them from tasting sweetness: - taste buds are receptors that bind proteins - different receptors for sour, bitter, salty, sweet & umami - sweet receptor made up of 2 proteins encoded by 2 genes: TAS1R2 and TAS1R3 10. In felidsTAS1R2 lacks 247 base pairs: - truncated, non-functional TAS1R2 protein ( sweet receptor does not form) 11. Are cats carnivores because they can't taste sweetness? - indicator of energy-rich carbohydrates - important in herbivores & omnivores 12. Felids tend to have lithe & flexible bodies with muscular limbs 13. In the great majority of species, the tail is between a third & a half the length of the body 14. Protractible claws 15. Skull highly domed with a short muzzle 16. Wide zygomatic arches & a large sagittal crest ( attachment of strong masticatory muscles) 17. Originally, it was thought that the domestic cat (Felis silvestris catus) descended from any one of five subspecies of wild cat: - Near Eastern wildcat (Felis silvestris lybica) - European wildcat (Felis silvestris silvestris) - Central Asian wildcat (Felis silvestris ornata) - Sub-Saharan African wildcat (Felis silvestris cafra) - Chinese desert cat (Felis silvestris bieti)