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Lecture

HSCI 216 Lecture Notes - Noncoding Dna, Mutation Rate, Nuclear Dna


Department
Health Sciences
Course Code
HSCI 216
Professor
Pablo Nepomnaschy

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HSCI216: LECTURE III
May 16, 2012
Question Period
o Next week 1st draft of term paper, next Friday midterm (first 4 lectures)
o Concepts are important, specific questions on point in video (because it relates to a concept)
o Mutation rates: (question ppl have trouble with) mutation rates vary across species,
within species genome across regions and between DNA’s (nuclear vs mitochondrial)
By observing we know mutation rates are different
Why: accumulation (not the rate of mutation) is faster in “junk” DNA
Mutation rate: how quickly/often in each generation do we see mutations
when mutation occurs in “functional” piece of DNA
Accumulation: how many of those do we see across a piece of DNA when
mutation occurs in non-functional piece of DNA
o This is how it is used as a clock ***
Places in the genome where mutation rate it hot/cold (fast/slow), there are places
where the genome contains places that help the human body become more efficient
(such as the immune system)
o Mitochondrial DNA mutates faster than nuclear DNA
Why? Only empirically we know, possibly mitochondrial DNA has more junk?
o Proximate explanation: how things happen? From a mechanism point of view
Ex: birds migrating when days get shorter the melatonin levels on the birds brain
start to increase then must eat more causing body temperature causing to go south
o Ultimate explanation: at some point, the birds or ancestors, of those who stayed north, had
less food and risk of death rose. Therefore an evolutionary explanation for why birds
migrate south.
Function/phylogeny: to avoid winter/
Life History Theory
o Ontogeny: development
o Biological fitness: how many offsprings you leave
Inclusive fitness: positive effect on the fitness of relatives
Nepotism: favoring family
Rb>c
o .5 is closest related (siblings, parents, kids)
o 1 is your own r value
o .25 is cousin
o this is a mathematical explanation for why someone would not save a
relative etc.
o optimizing resource allocation throughout the life span
energy used for one purpose, cannot be used for another
at each life stage, you will be allocating different resources, putting different
resources into things you have to do
ie: $30 total, use $10 for cake only once
o Humans have short birth intervals
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