CONS 302 - Module 1

major genetic questions

• what is the material controlling our traits/performance

• why do individuals differ

• how is genetic information inherited

two most famous biologists in history

charles darwin and gregor mendel

darwin famous for

the theory of evolution

darwin believed

all living organisms came from a common ancestor

darwins evidence

million living species evolved from a single celled common ancestors and genomics that all kinds of organisms share a large proportion of common DNAs

mendel theory

theory of classical genetics

mendel discovery

principle of inheritance and laid foundation of modern genetics

genetics

study of single genes, genetic variation, heredity in living organisms

genes

material controlling our traits

genetic variation

why individuals are different

heredity

how the genetic material is passed on

mendel focused on

heredity branch of biology

branches of genetics

classical, evolutionary, molecular genetics

importance of classical genetics

explains how genetic material is passed on from parents to offspring, cornerstone of modern genetics and genomics

classical genetics works

directly on traits

modern genetics/genomics works

on genes or genetic markers

gene initially defined

unit of inheritance

gene defined after chromosome discovered

small section of a chromosome

gene now defined

linear segment in the DNA molecule that encodes a protein or a functional RNA

alleles

specific variation of a gene

Genotype

specific combo of alleles for a given gene

phenotype

physical appearance of a genotype

genotype referred to

overall genetic makeup of a organism

phenotype called

trait

core of classical genetics

study the inheritance of genes from parents to children

before mendelian genetics believed

genetic materials from the two parents were mixed up then passed to off spring — blending inheritence

when mendel discovered inheritance summarized through

three laws of inheritance

mendel first law of inheritance

law of segregation one gene — one trait

law of segregation

each parents has two alleles for each trait and only one allele randomly passed on to an offspring

Mendel third law — dominance

for the two alleles of a gene the recessive allele will always be masked by the dominant allele

dominance in the third law

makes phenotype not always showing genotypes

homozygous

genotype with the same alleles at a gene - showing the genotype

heterozygous

genotype with different alleles at a gene - not showing the genotype

Test cross

used to reveal the genotype of an indivudal

how test cross works

individual in question is bred with an recessive homozygous individual for the trait

Codominance

form of inheritance where the alleles of a gene in a heterozygote are fully expressed

Albinism caused

by a recessive and lethal allele

Mendel second law of inheritance

law of independent assortment — two genes - two traits

law of independent assortment

different pairs of alleles are passed to offspring independently of each other

chromosome

DNA molecule with part or all of genetic material of an organism

chromosomes are in

pairs except gametes (sperm or eggs)

homologous chromosome

each pair - one from mother and another from father and each pair have the same genes except alleles variation

meiosis

part of reproductive process - cell division to produce reproductive cells

chromosome replication - meiosis

chromosomes copy themselves → cell divides twice → separate again creating 4 daughter sex cells → homologous chromosome exchange genetic material

linkage

genes on the sam chromosome can be inherited together

crossing over during meiosis

homologous chromosome exchange DNA and separating linked alleles to create new combo

when two genes not linked

follow independent assortment

when two genes linked what is used

rate of recombination to estimate distance between the two genes

linkage disequlbirum

alleles occur together more or less often than expected under statistical independence

relative distances of two genes

genetic map construcuted

genomics

discipline in genetics

genomics study of

organism entire set of DNA - genes, interaction with each other and the environment

genetics study of

single genes, genetic variation and heredity in organisms

genome

genetic material of an organism - DNA some RNA

genome includes

chromosome DNA and other DNA in a cell

two categories of organisms

prokaryote and eukaryote

prokaryote

unicellular organism, no membrane bound nucleus, bacteria and archaea

eukaryote

organism with complex cells, membrane bound nucleus, most organisms that we can see

bacterial genome - prokaryotes

bacteria with single circular chromosome and smaller circular DNA molecules called plasmids

small circular DNA in bacterial genome - prokaryotes

plasmids

virus genome - prokaryotes

some virus genomes made of DNA or RNA but is not living and instead infects all living forms

human genome - eukaryotes

human and other animal cells have chromosomal DNA and mitochondrial DNA

plant genome - eukaryotes

contain chromosomal DNA, mitochondrial DNA, chloroplast DNA

diploid

cells that have two sets of chromosomes - humans

haploid

cells that have a single set of chromosomes - sperm/egg

polyploid

cells that have three or more sets of chromosomes - crop plants

chromatin

complex of DNA and protein (histone) in eukaryotic cells

chromatin condenses

DNA forms

chromatin make

DNA from linear form into 3D strucuture

chromatin functions

prevent DNA damage, regulate gene expression, regulate DNA replication

DNA stands for

deoxyribonucleic acid

molecule of DNA has

two strands forming a double helix strucutre

DNA step on the ladder made

pair of bases

DNA - A base

adenine

DNA - C base

cytosine

DNA - G base

guanine

DNA - T base

thymine

DNA being a polymer

polynucleotide - repeating units

nucleotide 3 components

5 carbon sugar, phosphate, nitrogen base (one of the 4 letters)

DNA backbone - support structure

5 carbon sugar and phosphate form

nitrogenous bases

pyrimidines and purines

nitrogenous bases - pyrimidines

cytosine and thymine

nitrogenous bases - purines

adenine and guanine

Uracil - U

RNA only

paring role for the nitrogenous bases

A = T, C = G, A = U in RNA

DNA replication

process of producing two identical DNA molecules from one original DNA molecule

what happens to DNA during replication

double stranded DNA seperates and each serve as a template

components needs for DNA replication

primers, nucleotides, DNA polymerase

direction of new DNA synthesis

5 to 3

okazaki fragments

short pieces of newly synthesized DNA made on the lagging strand

lagging strand

the strand made in small pieces instead of all at once ne

importance of DNA replication

allow organisms to grow and pass genetic info to new cells/offspring

mitosis

division of the mother cell into two daughter cells genetically identical to each other

importance of mitosis

to increase the number of cells for growth in size

meiosis

type of cell division that makes genetically different gametes (sex cells)

meiosis produce

gametes (sex cells)

importance of meiosis for reproduction

makes cells with half of the number of chromosomes to combine during reproduction

independent assortment

chromosomes randomly mixed and separated creating genetic variation

crossing over

chromosome exchange pieces of DNA creating genetic variation