HSCI 216 Lecture Notes - Albinism, Mitochondrion, Gene Flow
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HSCI216: LECTURE II
Friday May 11, 2012
Tests will ask about facts that are logical, therefore understand concepts!
Multiple choice exams (40-45 questions) 2 can be true, one is stupid – use process of elimination
Go through notes, questions in questionnaires*, videos etc.
Evolution: change in the collective information contained in a populations genetic makeup.
o Start with a population with some info on one generation, then move to a next generation and
something changes causing evolution
o How does it happen? HEREDITY
o Heredity: transmission of information from one generation to the next. *
Basic mechanisms involved in the transfer of genetic information:
o DNA is organized in chromosomes (23, there are 2 copies)
o During cell cycle mitosis occurs (go over mitosis) how DNA goes from one cell to the next
o Meiosis: how DNA is inherited from person to person (go over meiosis)
divide into gametes cells (somatic cells – because “soma” is body)
How does genetic material change across generations…
o Mutation: change in the sequence of bases of DNA (review structure of DNA)
Sources of variation
Meiosis (recombination etc.)
o Meiosis (huge source of variation)
Recombination: happens when making gametes, the 2 chromatids get together,
when they cross they are sticky and they will get stuck. Thus causing variation.
They do not always cross at the right place causing change. This increases
number of genetic combinations
Then there is a process of combination of different gametes
o 98.5% of human genome does not code for protein because there are a lot of
regulatory systems in the DNA (the expression of the genes is going to determine how
the body works)
o not all base pairs are created equal
*phenotype does not only include physical features but behavior, personality etc.
(what we can perceive from them) ie: if body produces much cortisol then we
will react a lot, vise versa, thus showing how environment affects us genetically.
ie: womens hormonal levels during mentranaul cycle is part of her phenotype
based on the genes she has.
Not as “self contained”
o Alleles do not mix!
o Dominant allels masked recessive ones distinction between phenotype and genotype
o Genotype: genetic configuration
o Phenotype: outwards
Punnett square: everyone is hetrozyphis(?), this explains 3:1 ratio