M1 L1: Intro to Genetics Flashcards
How did we know humans had an understanding of genetics?
They knew about domestication and selective breeding to get certain traits in plants/animals
What was Aristotle’s view on genetics? Did it include epigenesis?
Semen has a vital heat that cooks menstrual blood into a fetus. Yes epigenesis
What is epigenesis? Who came up with the idea?
Fetus grows de novo in utero. It does not start as a tiny, fully formed human with proper limbs. William Harvey
What was the Hippocratic School of Medicine theory of genetics? Did it include epigenesis?
Believed humors from male body went into semen. The humors could be diseased or normal, and that influenced the development of the fetus. I don’t think it follows epigenesis?
What’s the Homunculus theory of heredity? Does it include epigenesis?
Semen includes a tiny fully formed human. Grows after implanting. No epigenesis
What’s the Ovist theory of heredity? Does it include epigenesis?
Egg contains fully formed human. Grows when stimulated by semen. No epigenesis
What’s the germ plasm theory? Who came up with it?
Ovaries and testes each have a full set of genetic info, egg and sperm each deliver half to offspring. August Weissman
What’s nuclein? Who proposed it was the genetic material?
Nucleic acid and peoteins. Edmund Beecher Wilson
Who discovered the first genetic disorder? What was it?
Archibald Garrod. Alkaptonuria, black urine disease
What 4 ideas led us to better theories of heredity?
1) Schleiden and Schwann cell theory: all life is made of cells; all cells come from other cells
2) louis pasteur refuted spontaneous generation: living matter can’t arise from nonliving matter
3) refuted fixity of species: species are not fixed; they have changed over time
4) natural selection: 3 premises, 3 conclusions for how species change over time
3 premises of NS
1) species have genetic variation, at least some is heritable
2) some heritable variation affects rates of survival and reproduction
3) species overproduce, produce more offspring than environment can support
3 conclusions of NS
1) there will be a struggle for existence among offspring
2) individuals with traits better fit for the environment will have more survival and reproductive success
3) adaptive traits will accumulate and the population will change through time
What’s blending inheritance? Who believed in it?
Offspring are the average value of the parents. Darwin
What’s the problem with blending inheritance? Who discovered this?
It’s incompatible with NS because advantageous traits will get diluted and never become fixed in populations. Fleeming Jenkin
What does diploid mean?
organism has 2 full sets of genes (maternal and paternal)
what is a gene
the functional unit of heredity
what are alleles
different variations of a gene
what’s haploid?
organism has 1 copy of each gene
what’s the chromosomal theory of inheritance? who discovered it?
Genes are on chromosomes. Sutton and Boveri
what’s the universality of mendelian inheritance? Who supported it? What debate did it start?
All inheritance follows Mendel’s fundamental rules. Inheritance is particulate. William Bateson. Biometricians vs. Mendelians on continuous traits
Biometrician argument? Who showed that Mendelian inheritance can explain continuous traits?
Continuous traits can’t be explained by Mendelian inheritance. Herman Nilsson-Ehle, Edward East showed it’s possible if the trait is governed by multiple genes
Who confirmed the chromosomal theory of inheritance and how?
Thomas Hunt. Red eye WT flies vs white eye mutant flies.
source of all genetic variation?
mutations
why did people think proteins were the hereditary material, not DNA
proteins are made of 20 different animo acids which would allow for greater complexity. DNA is made of 4 different nitrogenous bases which shouldn’t result in as much complexity
3 structural differences between DNA and RNA
1) DNA is double stranded, RNA is single
2) DNA has thymine, RNA has uracil
3) DNA has deoxyribose, RNA has ribose
What bonds are in DNA
1) covalent phosphodiester bonds in the backbone (between phosphate and sugar)
2) hydrogen bonds between nitrogenous bases
components of a nucleotide
1) Nitrogenous base
2) ribose or deoxyribose
3) phosphate
What is the central dogma
DNA gets transcribed into RNA, RNA gets translated into proteins
How does a change in a nucleotide cause sickle cell disease?
Change nucleotide causes a change in RNA –> change in animo acid –> change in protein shape –> a change in protein function –> sickle cell disease
Why do we use model organisms like mice, bacteria, yeast, and flies?
1) fast generation
2) easy to manipulate
6 pieces of evidence of LUCA
1) all orgs use universal genetic code
2) all orgs use central dogma
3) all orgs composed of common chemical parts (DNA, RNA, amino acids) and structures (membrane bound organelles)
4) all orgs extract energy from environment
5) all orgs have homologous genes from a LUCA
6) all organisms evolve through gradual changes in genetic info
Who came up with the 3 domain model
carl woese
what is a chromosome
a structure in cells that encode the genetic material of the organism. made of DNA and proteins
2 key differences between meiosis and mitosis
1) mitosis makes 2 identical diploid daughter cells, meiosis makes 4 different haploid daughter cells
2) mitosis has one equational division, meiosis has one reductional division then one equational division
what is a mutation
any heritable change in DNA
what is base complementarity? how does it relate to DNA replication?
A and T or U always pair, and C and G always pair. in DNA replication, if you know one strand, you can make the other strand because it must complement the original
what’s the role of tRNA?
They translate RNA into proteins by bringing the correct amino acids to the ribosomes
Describe gel electrophoresis. What does it assay?
there’s a gel placed in a buffer solution. samples of DNA are pipetted into wells near the negative electrode side of the gel. when the apparatus is turned on, the DNA is pulled to the positive side of the gel because phosphate groups make DNA negatively charged. the distance the strands traveled indicates their size. shorter ones travel farther than longer ones.
