Domestication Flashcards
Who did dogs descend from?
Grey wolves
When were dogs domesticated?
j
Where were dogs domesticated?
j
How many times were dogs domesticated?
s
Why/how did domestication happen?
s
Which of the 5 questions do we have a definite answer to?
Who did dogs decesnd from
What are the 5 domestication questions?
Descended from whom
When
Where
How many times
Why/how
How do we know dogs are the same as wolfs?
They can reproduce and have fertile offspring
Where does evidence come from to help us understand domestication?
Archaeology and Genetics
For most of the 20th century, when did archaeological evidence suggest dogs were domesticated?
approx 15,000 years ago
For most of the 20th century, where did archaeological evidence suggest dogs were domesticated?
Eurasia or middle east
How did evidence date the domestication of dogs?
3 answers
Radiocarbon dating
where the fossils were found
with what humans they were found
What did we have no idea about
how many times dogs were domesticated
The ancestral species
Where was the jaw fragment found in 1873
Kesslerloch Cave, Switzerland
When was the jaw fragment from 1873 reanalysed?
2010
what method was used on the reanalysis of the jaw fragment found in 1873 in 2010?
Radiocarbon dating
What is compared when looking at wolves – dogs
5 points
Muzzle length
Brain case size
Tooth size
Tooth spacing
Jaw width
What happens to tooth size - wolf to dog?
Smaller
What happens to jaw length wolf to dog
shorten
How do researchers work out what changed first - wolves to dogs?
They piece together evidence/clues from bones
Does it all change in the same order when looking at bones
No!
What did the 2010 reanalysis of the jaw fragment show
This was the oldest undisputed dog fossil. It’s definitely a dog and supported the notion dogs were domesticated 15k years ago
What did the Belgian researcher say?
She has evidence - archaeological and genetic, that they were dogs 28-40k years ago
So when were dogs domesticated?
15k or 28-40k years ago!!
Where did the fossils come from to support the Belgian researcher’s view
3 answers
Belgium, Czech Republic, Siberia
Why is there a discrepancy in the dates of domestication?
What criteria are individuals using to define wolves and dogs?
Early dogs were likely backcrossed with wolves, many times in many different places
Can both early dog and late dog arguers support their case?
yes!
What is the early dog arguers saying
30k years ago
What are the late dog arguers saying
15k years ago
What were people doing with early dogs?
Nobody knows
What hypotheses are there in regard to domestication
Coppinger - self-domestication, less flight distance followed by humans then using them for hunting etc
Deliberate domestication for hunting etc?
Both?
What were early dogs used for?
Hunting
Drafting
Guarding
What do we have to tolerate in regards to domestication?
Uncertainty!
What did they find in Texas?
Evidence of humans having eaten dogs!
Is it cheap to research domestication
No!!
Why is there interest in dogs genetics?
There is a benefit to us in understanding where to look in the human genome for markers for genetic disease
How do we decipher a genetics paper?
What’s a haplotype?
set of DNA markers that tend to lie close together and be inherited together
Shows if an individual is part of a population or not
What is a marker
informative sequence on the chromosome - this DNA tells us a lot
How do we determine how reliable relatedness is?
The more markers that are tested the more reliable the estimate of relatedness
What can haplotype tell us
Relatedness and groupings
Breeds
Brother/sister
Population
Why is the fingerprint in haplotypes different?
It isn’t unique to an individual in genetics its a marker of a group
What is a microsatellite?
A place in the genome where there is a bunch of repeats
What does a microsatellite tell us?
the number of repeats informs us about relatedness to someone else.
If they have the same number of repeats in the same place in the genome it informs relatedness between individuals, populations (dogs, Asian dogs, chows etc) and species
What does it mean when there isn’t much variation on the microsatellites?
It tells us related species on a big scale - e.g. mouse c.f. chimp c.f humans
What does it mean when there is moderate variation on the microsatellites?
It tells us this is a population within a species
e.g. breeds, wolves vs. dogs, groups of breeds!
What else can moderate variations on the microsats. tell us
Which breeds are related to which
If you have 2 individuals with the same microsatellites?
It’s uninformative, they could be in one group or the other if the alleles are found in both populations
What do 21st C. genetics papers show us
2002 2 big genetic studies suggesting 15k years ago in a single domestication event in East Asia
2004 Parkers et at proposing a split off order for 85 breeds
What was looked at in 2005 Lindblad-Toh and in what species
Sequences in rodents, primates and dogs
What does analogous mean?
Looking or being almost but not exactly the same
What was Lindblad-toh looking at on the genome?
Analogous sequences found over and over and over
Analogous sequences found over and over and over are what
important! they suggest relatedness
What did Lindblad-toh find?
Most conserved (keep finding the same sequences) non coding sequences cluster near a small set of genes that play important roles in development
What was a big takeaway from the Russian fox experiment
Development events timing changed
Delayed timing of socialisation/fear period
Eyes opening timing
More puppy like adult
what was studied in 2010 in regards to SNP to help understand domestication
one change in a string of haplotype analyses e.g. changing a T for a G in one place
What did the 2010 study show? In regards to the ancestral environment
Middle East showed greater diversity which suggest this was the ancestral environment
What is a Cladogram?
Based on morphology (measurements of bones/skulls or genetically etc) constructed into a relatedness diagram.
What doesn’t a Cladogram show you?
Who came in which order!
What is a haplotype-sharing phylogram?
Sharing of important haplotypes and grouping relatedness together
Are there discrepancies in genetic papers?
yes
How do we explain the discrepancies in genetic papers
The population sampled - size, who, where from
Biases of researchers (samples)
What they are looking at (Nuclear/mitochondrial DNA)
Who do you get mitochondrial DNA from?
Mothers
What is proto-domestication?
The very beginnings of domestication - there are likely 2 stages
What specific findings have researchers found in regards to genetic studies 3
1 specific gene expression differs between dogs and wolves (expression - other genes that turn this gene on or off). A mutation of this exact gene causes Willam’s syndrome.
Chicken domestication research on the thyroid has turned up a gene mutation between them and their ancestors where the domestic chickens are less spooky & breed more.
Dogs are adapted to digest starch (March 13)
What is Williams syndrome?
Humans
Causes friendly outgoing nature
