Genetic Variation

Question 1

Beta Globin: 3 allele

Answer 1

A, S, C

remember beta globin is Part of what makes up hemoglobin (2 betaglobin, 2 alphaglobin)

Question 2

A allele

Answer 2

Normal
o GAG
o Glutamic acid
o HbA: 2 A alleles (in both b-globin subunits, 1 in each b-globin subunit)

Question 3

S Allele

Answer 3

o GUG
o Valene
• HbS: 2 S alleles (1 in each b-globin subunit)

Question 4

C Allele

Answer 4

o AAG
o Lysine
• HbC: 2 C alleles

Question 5

SA

Answer 5

o	Some sickle shaped cells
o	Mild form of blood disease
o	Beneficial b/c provides partial protection against severe malaria
o	May have shortened life span
o	Will have affects of anemia
o	Heterozygous

Question 6

CC

Answer 6

o More protected from malaria
o Very mild form of anemia
o Doesn’t require medical treatment

Question 7

SS

Answer 7

o Seveerly affected by Sickle Cell anemia

o S allele encodes for collapse, two of them means you make only sickle cell shaped cells

Question 8

Emphysema

Answer 8

o Alpha1 antitripson gene
• Makes enzyme to bind to elastase
• Inhibits elastase

Question 9

Elastase

Answer 9

• Break down elastin and keep perfect balance between old and new elastin

Question 10

Nondisjunction

Answer 10

is the failure of a pair of chromosomes to separate during anaphase of cell division.
can occur in as many as 10% of meotic divisions
major cause of spontaneous abortion

Question 11

Emphysema (More)

Answer 11

onset in middle age
shorten life 10-30 yrs
can probably pass to offspring (b/c late onset)

Question 12

Emphysema Phase 1

Answer 12

Environmental Interaction
o Ciggaretes affect action of enzyme mentioned
• Affect inhibition of protein who breaks down elastin
• Too much elastin break down
• Loss of lung elasticity→ emphasema

Question 13

Emphysema Phase 2

Answer 13

o	Mutant form of alpha1antitripson genes
•	Pis allele mutated
•	Enzyme has lower affinity for elastase
•	Doesn't bind it as it should
•	Doesn't inhibit it right
•	Decrease lung elasticity→ emphesema

Question 14

Oogenisis

Answer 14

• Go through meosis I, wont resolve meiosis II until much later
o Developing egg cells in limbo
o Imporoper connection of microtubules to centrosomes
• Bad pulling
• Because eggs spending more time in limbo stage

Question 15

Beneficial Mutations

Answer 15

• Reduction of succeptibility to HIV
o env region in HIV genome encodes surface glycoprotein
o glycoproteins on surface of virus interact with and be accepted by CD4 surface protein AND CCR5 co-receptor to get access to the cell
what version of CCR5 co-receptor you have determines succeceptibility

Question 16

CCR5 Alleles

Answer 16

• Homozygous for normal CCR5: succeptiable to HIV
• Heterozygous for delta 32 mutation: delay in progression of AIDS by 2 years
• Homozygous for delta 32 mutation: reduced ability of HIV to infect cell
o PROBABLY NEVER GET AIDS

Question 17

Delta 32

Answer 17

deletion of 32 nucelotides: 1 nucelotide short of deleting 11 amino acids and keeping the rest in frame
o	SHIFTING CODING FRAME
o	Premature stop 
o	Truncated CCR5 protein
o	Cant be recognized by virus

Question 18

Why Delta 32?

Answer 18

• Probably in the past conferred resistance to black plague and small pox
o So increased frequency of delta 32 in Europe

Question 19

Variable Number of Tandem Repeats (VNTR)

Answer 19

regions that help identify us at the genetic level
• DNA fingerprinting
• Based on variable number of tandem repeats
• About 30 base pairs long
• Number is variable 6, 10, 30, 40 whatever
• PCR to amplify that region of the genome
• PCRing produces bands of different lengths
o Size will differ based on number of repeats
• One band: 2 copies of same allele
• 2 different bands: different alleles (heterozygous)
• Need to amplify hundreds of regions of genome

Question 20

Restriction Fragment Length Polymorphism (RFLP)

Answer 20

• Another way to fingerprint
• Restriction enzymes
o cut DNA at specific nucleotide sequence
• Restriction enzyme recognizes a sequence, makes a cut
• Things that aren’t restriction enzyme sequences aren’t cut
• Probe to detect fragments
o Load into gel, run it out
o Long band migrates more slowly
• Transfer using Southern Blot to membrane
• Probe membrane
o Probe recognizes thingy
• When blob recognized, can determine genotype
• Homozygote AA
o 1 band
• Heterozygote: 2 bands
o No cut in S
• SS genotype: 1 band

Question 21

Copy Number Variation (CNV)

Answer 21

• Tandem repeats
• Copies
• Or Deletion
• Genotype microarrays
o Useful for detaching copy number variation, differences among indivs in number of copies region of genome
o CNV: large and can include 1+ complete genes

Question 22

CVN Genotyping

Answer 22

•	Fluresnce technology
•	probes:
o	amylase gene (starch break down)
o	Populations with high starch diets, 
o	Have lots of copies of analyase gene
•	A whole extra one compared to non high starch diet

Question 23

Single Nucleotide Polymorphism (SNP)

Answer 23

Look at SNPs across indivs in a pop, where are they different at SNPs?
• Eye color
o Look for associations between alleles and pheonotypes
Just Correlation

Question 24

Eye Color SNPs

Answer 24

o C-G allele: Blue Eyes
o T-A allele: Brown Eyes
o THESE GENES ARE NOT IN THE ACTUAL GENE FOR MELANIN MAKING COLOR. They are downstream
o 94% with CG had blue eyes, only 2% had brown eyes
o Down stream, is associated with expression of melanin gene
o CG downstream, decreased expression of melanin, blue eyes
o TA downstream, normal melanin expression, brown eyes

Question 25

Nondisjunction in Meiosis I

Answer 25

• both homologous chromosomes migrate to same pole
• daughter cell has 2 copies of a chromosome, should only have one
• Gametes: none are good, two have an extra version of a chromosome
• Two are missing completely a chromosome
o Most likely no viable gametes
o But sometimes you can produce viable offspring (the ones with extra

Question 26

Nondisjunction in Meiosis I results

Answer 26

o 2 gametes with extra copy of chromosome
• trisomy
o 2 games lacking chromosome (monosomy)
o Down syndrome

Question 27

Nondisjuntion in Meiosis II

Answer 27

o Pulls both copies two one side
• 2 good gametes
• 1 missing the chromosome
• 1 with an extra copy of the chromosome

Question 28

XXX

Answer 28

o : not a big deal
o X inactivation
o Only genes on 1 X are being expressed anyway

Question 29

XYY

Answer 29

o Ok, not much on Y chromosomes anyway

slightly taller people

Question 30

XXY

Answer 30

Kleinfelter
o	Tall
o	More feminine features
o	Small testes
No normal X inactivation

Question 31

X

Answer 31

Turner
Short
o	neck and skin webbing
o	poor breast development
o	cant have children
•	poorly developed ovaries

Question 32

Polyploid Organisms

Answer 32

• many fetuses that go spontaneous abortion
o triploid or tetraploid (3 or 4 complete sets of chromosomes) eggs
• defective spindle apparatus

Question 33

Nondisjunction Results out of 10000 births

Answer 33

o 8000 have major chromosomal abnormalities
o 7500 spontaneous abortion
o 500 live births

Question 34

Extra or Missing Chromosomes in Live Births

Answer 34

Trisomy 21: three copies of 211
• 1 of 155 live born childen have chromosome abnormality
• down syndrome most common
o trisomy 21 or 47, +21 (47 insread of 26 b/c of extra in 21)
• trisomy 13 and 18
o only live about 1 year

Question 35

Translocations

Answer 35

Bits of chromosomes that are swapped to different chromosomes