Gentetics 2153 Larkin Test 2

Cytogenetics

microscopic study of chromosomes

Karyotype

rearranged microscopic m=image of a persons's chromosomes, usually used to identify certain chromosomes.

Polyploid

extra complete sets of chromosomes

1n=1 set

Aneuploidy

a change in a set of one chromosome (addition or subtraction)

ex. trisomy 21

kleinfelter XXY

Turner XO

Nondisjunction

Whenever homologous chromsomes don't separate correctly during metaphase I or II

Metaphase I = chromosomal

Metaphase II = chromitid

Changes in Chromosome Structure

Original: ABCDEF

Deletion (Deficiency): ABEF (Ex. Cri-du-chat deletion of fifth chromosome)

Duplication: ABABCDEF

Inversion: ABDCEF

Translocation: Exchange between two different chromosomes

Chromosomal Inversion

Sometimes a chromosome will form a loop to match the inverion

Reciprocal

Translocations involving 2 chromosomes

altered pairing of translocation homologues in meiosis can cause missegragation (ex. Burkitt's Lymphoma b/t 8 and 14)

Crossing over occurs...

in prophase I of meiosis

Crossing over

exchange of DNA b/t chromosomes homologues

Genes on the same chromosome often do not assot independently. (T/F)

True

With crossing over how many more gametes can we create than without?

Two more with a total of 4 gametes:

AB Ab aB ab

Genetic Map Distance

# of recombinants/ total progeny * 100 =

measured in centiMorgans or cM

How do you test for Recombination?

See if it assorts independently according to the null hypothesis. Use X^2 test

Wild-type

the "normal" variation of an organism (none for humans)

Alfred H. Sturtevant

studied enetic linkage under T. H. Morgan

Figured out that you could estimate the didstance b/t genes by recombintion frequency

Two crossing over sites are always detectable? T/F

False

Mximum recombination is

50% (identicl to independent assortment)

Recombination classes

smallest classes

Double recombination classes

usually single digit # progeny

Seawall Wright, JBS Haldane, and RA Fischer

people of population genetics

Where does variation in populations come from?

Mutation

Hardy-Weinburg Equallibrim

p+q=1

p^2+2pq+q^2=1

p= dominant allele

q= recessive allele

P^2 = AA

2pq = Aa

q^2=aa

Do allele frequencies change from generation to generation?

It only doesn't in HW Equalibrium

Heterozyygots among dominant phenotypes

2pq/(1-q^2)

Assumptions of HW Equalibrium

Large Population size

no migration

no mutations

no selection

Random mating

Evolution

change of allele frequencies in populations

Mutation

only way new alleles are introduced into populations but the slowest at changing allele frequencies

selection

fastest way to change allele frequencies in populations. Also only HW exception that leads to adaptations

Fitness (W)

average number of offspring given in a given population or genotype

Relative fitness

genotype with the largest population is assigned W_>=1.

and the relative fitness of the other genotypes is determined relative to the most fit.

selection coefficient

The differenc e in relative fitness between the most fit and a genotype

stands for the difference in how many fewer offspring the genotype create relative to the most fit

Fitness can be different in different environments. (T/F)

True

Balancing selection

in sickle cell the selection for the heterozygotes is strong enough to preserve the recessive s and counter the selectin against recessive homozygotes

In 1900...

Nucleus was discovered that it contained a large amounts of a P, N, and carbohydrates- otherwise known as DNA (less complex than proteins)

Most people in 1900 believed this was genetic material?

Protein

F. Griffith

Discovered genetic transformation in sterptococcus

pneuminiae

something in heat killed bacteria

caused a pheotypic change in bacteria

transformation

getting a genetic change in a cell or organism

Who discovered that the DNA was probably the transforming substance?

Avery, Macleod, and McCarty

E. coli Virus

T4 Bacteriophage

Viral Life Cycle

Absorption by cell

entry of viral gnetic material

synthesis of viral compounds

maturation of virions

lysis of cell when done

Alfred Hersheyand Martha Chase

Discovery that DNA was the material that bacteriophages used to infect cells

they used ionic markers of P32 and S35 o discover this

HIV

RNA core

reverse transcriptase

Envelope (lipid bi-layer)

HIV life cycle

reverse transcription of RNA to DNA

Integration into DNA host genome

Prodution viral mRNA, Viral protein, and viral RNA genome

assembly of mature viruses and budding off surface

3 main parts to DNA

Sugar

phosphate

nitrogen base

DIfferences with RA

Riboe sugar (hydroxyl group on 3 carbon atom)

Uracil instead of thymine

usually single stranded

Structure of a nucleotide chain

Phsphodiester bond (phsophat with RC--OOR

5' (Nitrogen base) to 3' (Phosphorous)

Watson and Crick

Discovered DNA structure

Chagaff

Discovered adenine and thymine concentrations were the same, and thus concluded the same was true for guanine and cytosine

Rosalind Franklin and Maurice Wilkins

Had X-Ray Diffraction data for DNA structres

concluded double helix

concluded 3.4 nm per spiral

DNA has...

antiparallel bonding and base pairing held together through H-Bonds

Eukaryotes have a ...

larger genome than prokaryotes and thus need a higher compaction of DNA

E. coli genome length

1 mm long

Human genome length

2 meters long