DOG- Unit 2

Proto-Domestication (1st)

100,000-50,000 Anthropogenic and non-anthropogenic population

Transitory Domestication (3rd)

15,000-7,000 True dogs Lots of archaeology

Modern Domestication (5th)

2,000 to present modern breeds 200 years to present Tons of new breeds

Codon

3 base pairs that code for amino acids and allow amino acids to make up proteins.

1966 to 1973

5,000 dogs served in Vietnam Estimated to have saved over 10,000 lives Indication of our changing view of dogs (most military dogs were euthanized) Now most are reunited.

Early Domestication (2nd)

50,000-15,000 Anatomical changes

Late Domestication (4th)

7,000-2,000 Diversification of dog breeds

Village Dogs 2015

85,805 genetic markers 4,676 pure breds from 161 breeds 549 village dogs from 38 countries. Suggests both a Central Asian and Eastern Asian origins at 33,000 years.

Starch

A kind of carbohydrate (disaccharide) which requires enzyme action in small intestine before it is hydrolyzed and used by the body for fuel.

Sighthounds

A kind of hunting dog "Gaze-hound", grey hound-type Most ancient identifiable breed type still around today in all analyses (genetic, archaeological, historical) Hunt based on sight Superior vision to other dog types Commonly depicted in ancient Egypt pottery, sculpture, paintings over 5,000 years ago.

Breed

A selection of outward physical traits and the predictability of breeding "true" to physical standards.

Village Dogs 2009

A study challenged the sampling bias and used the whole genome of village dogs. Estimated exact location south of Yangtze River at about 5,400 to 16,300 years ago.

Village Dogs 2006

A study that included African village dogs showed that they had similar levels of mtDNA diversity.

Dietary Niche Expansion

Although wolves are generally carnivorous, they have flexible diet and scavenge. Human activity provides multiple sources of food. Influence of endocrine system

Co-Evolution

An evolutionary change in a trait in species 1 in response to a trait in species 2, followed by an evolutionary response by species 2 to the change in species 1.

Molecular Clock Hypothesis

As time passes, genetic differences accumulate within and between species. Rate of mutations and molecular change is constant (enough) to predict times of divergence.

Cryptic Diversity

Aside from new mutations, cryptic variation in wolf ancestors explains how it is possible to get so many different forms over a short period of time.

Human Health and Medicine

Assistance for visually disabled Seizure alert Cancer detection PTSD Human longevity and aging

2nd

Baldwin Effect

Wolves Self Domestication

Behavioral Ecology Variation in Wolves Dietary Niche Expansion Natural variation in fear response and flight distance

1st

Behavioral flexibility and phenotypic plasticity

Cairo

Belgian Malinois military working dog 2011 vital to US Navy SEALS "operation Neptune Spear" in which Osama Bin Laden was killed.

Cryptic Variation

Can emerge through shuffling of genetic material and allows evolution of traits at a much faster pace and also exceeding original range. Acted on by artificial selection

Origins of Domestication

Central Asia East Asia Europe

Genetic Drift

Change in gene frequency due to random sampling of genes from one generation to the next. Same alleles can increase, others may get lost.

19th Century Dog Domestication

Charles Darwin Multiple canine species yield the many breeds we have today

Factors and Processes Influencing Domestication

Combination of: Wolves altering their behavior (self-domestication) Humans selecting traits Both species co-evolving

Mitochondrial DNA

Contained in mitochondrion organelles in every cell's cytoplasm Inherited from mother (egg is larger than sperm) Single stranded Can pass through the nuclear membrane.

Nuclear DNA

Contained in the nucleus of cell Double stranded Complete set of DNA in nucleus is called the genome.

Examples of Cryptic Variation

Corn- 4 to 6% oil content in 1st generation corn. Some corn plants have hidden genes for increased oil content. Artificial selection for increased oil content allowed this cryptic variation to surface. Fox Experiment

Two Types of Genetic Variation

Cryptic Expressed

27,000-40,000 Years

Current estimation of when dogs began to diverge from wolves using whole genome sequence.

Behavioral Ecology Variation in Wolves

Differences in habitat and food availability influences foraging behavior. Humans provide novel, easy to exploit new source of food that wolves ate: new niche! Dogs are descendant of wolf populations that relied more on scavenging on human foods. Natural selection and artificial selection pressures different on these populations than on non-scavenging populations resulted in change. Process of adaptation of wild animals to humans without direct human selective breeding Most likely started as a result of niche expansion into a new available resource: human food remains.

Alleles

Different forms of Genes

Why Genetics?

Dog breeds incredibly diverse, even Darwin was perplexed as to how there can be so much diversity. Modern breed ancestry can be traced back by looking

Influence of Endocrine System

Dogs and humans have amylase (twice as much as other animals). Convergent evolutionary event to allow dogs to subsist off of human garbage in agricultural societies.

Genetic Evidence

Dogs evolved from wolf ancestors that had greater diversity than modern wolves. Modern dogs evolved from wolf ancestor that is now extinct. Modern grey wolves and modern dogs share a common ancestor. Domestication probably took place in at least 3 sites of origin. Evidence of specific dietary adaptation to human's diet- dogs are better at eating starchy foods than wolves. Dog domestication probably took place sometime between 15,000 and 40,000 years ago but exact location is uncertain and self-domestication was probably occurring previous to 40,000.

General Pattern of Cultural Technological Advances

Domestication and diversification of dog types runs in parallel with advances and changes in human technology and cultural diversity.

Current Dog Domestication

Domestication of grey wolf populations throughout different regions of Eurasia (not clear on which subspecies). Over the years many theories have been proposed. Understood now that there were multiple interacting factors and processes (non-exclusive).

130,000 Years

Early estimates of when dogs began to diverge from wolves based on the molecular clock approach.

Cultural Technological Advances

Early on, dogs just played a role in guarding and perhaps as food. As human populations spread, settlement increased, and culture diversified humans found ways to use dogs for different tasks involved herding, pulling sledges, and guarding. Humans with dogs have a hunting advantage.

1200s to 1500s

Era of origins of most modern breeds, especially hunting Although some much later (golden retriever 1870) Lots of hunting breeds because hunting was a symbol of power and status for Western European aristocracy laws of Hunting (venery) established

How to Use the Molecular Clock

Evaluate frequency and patterns of mutations in different populations of a species Assume mutation rate From this, can determine when populations diverged.

World War I

Extensive use of dogs for tracking, delivering messages, detecting mines, finding victims, and pulling carts. Poor records but estimated that >1 million dogs killed in service.

Proto-Dogs

Filled new ecological (food niche) Would have needed to be able to follow rapid changes in human life style

Later Sources of Food

Garbage at settlements

3rd

Genetic Assimilation

Dogs Used in WWII

German Shepards Doberman pinscher Collie Belgian Malinois Malamutes Huskies

Consensus on Dog Domestication

Grey wolf is the ancestor and closest living relative of dog.

Mutations

Heritable change (mistake) in DNA molecular structure often in replication phase. Many breed-defining traits are caused by small genetic changes

Thyroxine

Hormone secreted by thyroid Governs growth and maturation Governs adrenaline (fear response)

Human Selecting Traits

Human choice of pups Orphan wolf pups Although humans eventually started to selectively breed dogs for particular traits, it is highly unlikely that this is how the process of wolf domestication was initiated.

Genetics of Starch Digestion

Human populations that consume a lot of starchy foods have more copies of the AMY 1 gene and therefore produce more salivary amylase. Like most mammals, dogs don't have salivary amylase (AMY 1) , but they have 4 to 30 genes for AMY 2. Wolves only have 2 copies for AMY 2.

Breed "Types"

Hunting dogs Guard dogs Sheep dogs Lap dogs

Important Roles of Dogs Today

Increasing role diversification with increasing recognition of dog intelligence, ability, and behavioral diversity. Human health and medicine Warfare and Military

Historical Records from Ancient Rome

Indicate knowledge of: selective breeding morphology and behavior were inherited Early training was critical What features dogs should have

Dog and Human Co-Evolution

Interactions between two species that result in evolutionary shifts (genetic change) in both species as a result of the other. Early proponents of which dogs helped humans exploit resources in new ways. Neurophysical and behavioral co-evolution Dogs have taken over the job of orienting in the environment because of their superior olfactory sense.

Expressed Variation

Is operated on by natural selection.

How Variation is Maintained in a Population

Large breeding populations Gene flow in sub-populations Natural selection continually shuffles frequencies of traits between generations Sexual reproduction and recombination Cryptic Variation

Warfare and Military

Long history in Ancient Egypt, Greece, Persians and Romans.

Self Domestication

Lowered fear/ shorter flight distance becomes more common in populations and after many generations have a subspecies that is comfortable with humans.

DNA Strands

Made up of adenine, thymine guanine, and cytosine The sequences of these bases determines sequencing and protein synthesis.

Example of Small Population

Mexican grey wolf Founding population was just 7 individuals and now they are also isolated from other breeding populations No gene flow

Afgan Hound

Most ancient breed living today Bred in Afghanistan 5,000 years ago.

Modern Breeds

Most appear within the last 200 years 400 breed on the planet The American Kennel Club Recognizes 167 breeds

Gene Flow

Movement of genes between populations Migration and mating Limits differentiation between populations (i.e. maintains similarities) Can only occur within a species Often interrupted by geographic features.

Dog Domestication

Multiple views on how, when, where domestication took place. Not clear on which subspecies of canis lupus (single or multiple) and exactly how and when domestication occurred.

Processes Influencing Genetics

Mutations Gene Flow Genetic Drift

Behavioral

Need to know perceptual world of a species to fully understand its behavior.

Timeline of Domestication

Not fully clear (only have a few pieces of the evolutionary and historical puzzle) Data from archaeology and genetics. Generally, dog domestication from wolves tied human migration throughout Eurasia and human habitat use and resource extraction. In order to understand dog domestication, need to understand what humans were doing for the past 100,000 years.

Village Dogs

Not like most modern breeds that have been under intense artificial selection. Considered representative of ancestral 'pre-breed' (land race) populations around the world. Sampling of village dogs shows higher genetic diversity in East Asia. Older populations have had more time to accumulate mutations, so higher diversity.

Two Forms of DNA

Nuclear Mitochondrial

Orphan Wolf Pups

Orphaned animals fairly common, humans adopt Wolves are particularly easy to tame and socialize if process is started before 21 days old.

AMY 2

Pancreatic amylase

Early Sources of Food

Remains at human hunt sites

500 BC to 500 AD

Roman period most of the main breed types that exist today had been developed (hunting, guard, sheep, and lap). Historical records

AMY1

Salivary amylase

Archaeological Data Limitations

Scarcity of finds Difficult to differentiate bones of domestic and wild populations as changes were gradual.

Multiple Uses of Dogs in Warfare and Military

Scouts Sentries Trackers Patrol Used in battle since at least 800 BC (Greece and Rome) 1500s, mastiff-like dogs used by Spanish conquistadors.

Evolutionary

Sensory and perceptual systems under intense natural selection pressure.

Dog Genome

Sequenced in 2005 Has allowed for robust understanding of differences among breeds and what genetic changes took place between breeds and between dogs and wolves.

Gene

Sequences of amino acids in a region. Unit of information about a trait that is passed from parent to offspring.

Example of What Features Dogs Should Have

Sheep dogs should have white to distinguish from wolves and guard dogs should be black to be threatening.

Example of Mutations

Short legged phenotype associated on chromosome 18 Chondrodysplatic (short-legged) Non-chondrodysplatic (long-legged)

AKC Breed Groups

Sporting Hounds Terriers Working Herding Toy Non-sporting

Amylase

Starch enzyme Two kinds

Village Dogs 2010

Study looked at many more genes (48,000) and found evidence for multiple sites of origin: Middle East, Chinese, European wolves.

Village Dogs 2002

Suggested village dog divergence proposed at 15,000 years. East Asian origin result possibly due to mostly sampling village dogs from E. Asia.

Human Choice of Pups

Suggestion that humans may have picked the wolf pups from the den. Observation: there is always variation in wolf pup temperament and behavior towards humans. After socialization with humans, some pups exhibit "correct" temperament and were selected for over many generation.

Dog "Types"

The genetics of most modern breeds indicate that they are not truly "ancient," but actually recreations (19-20th centuries) of earlier "types."

Natural Variation in Fear Response and Flight Distance

Thyroxine HPA-axis Neural Crest Cells Wolves with lower fear and shorter flight distance more likely to survive and reproduce because they have greater access to foods associated with humans. Traits associated with being able to exploit these new foods (endocrine, behavioral) will be present in offspring.

WWII

US marine corps used dogs extensively in Pacific and European theaters. All dogs with the appropriate temperament were chosen and donated by their American owners but some stood out.

US Military Today

US military deploys >500 dogs and their soldier handlers each year. Cairo Highly specialized

Laws of Hunting (venery)

Use of different dog types for different hunts formalized. Who could use what dog.

Perceptual World of the Dog

Vision Hearing Olfaction Behavioral Evolutionary Basically an interspecific and comparative investigation. Typically use humans as a reference species.

Small Populations

Vulnerable to both genetic drift and mutations

Sgt. Stubby

WWI American Pit Bull Terrier given rank of sergeant when he discovered, captured, and alerted allies to presence of German spies.

15,000 to 40,000

When dog domestication started to take place. Proto-domestication probably took place before 40,000.

Genetic Drift and Founder Effect

When small segment of a population is reproductively isolated from larger population. Causes smaller population to genetically diverge. Increase variation on species level, decrease variation in a population

2002 Dog Domestication

mtDNA study demonstrated that it was a grey wolf population in East Africa.