Population Genetics Ch. 23 and Beyond; Lab/Lecture Same

Math Calisthenics I

Ladybug Population Generation One

Calculate TOTAL # A

AA = 200

Aa = 100

aa = 200

Calculate Total # a

Math Calisthenics I

Ladybug Population Generation One

Calculate TOTAL # A

(200 X 2) + (100 X 1)

Total A = 500

AA = 200

Aa = 100

aa = 200

Calculate Total # a

(200 X 2) + (100 X 1)

Total a = 500

Calculate TOTAL # A

(200 X 2) + (100 X 1)

Total A = 500

Convert to % A

Calculate Total # a

(200 X 2) + (100 X 1)

Total a = 500

Convert to % a

Calculate TOTAL # A

(200 X 2) + (100 X 1)

Total A = 500

Convert to % A

500/1000 = 0.5

(AVOID USING 50%)

Calculate Total # a

(200 X 2) + (100 X 1)

Total a = 500

Convert to % a

500/1000 = 0.5

(AVOID USING 50%)

Ladybug Population Generation Two

Calculate TOTAL # A

AA = 300

Aa = 100

aa = 100

Calculate Total # a

Ladybug Population Generation Two

Calculate TOTAL # A

(300 X 2) + (100 X 1)

Total A = 700

AA = 300

Aa = 100

aa = 100

Calculate Total # a

(100 X 2) + (100 X 1)

Total a = 300

Calculate TOTAL # A

(300 X 2) + (100 X 1)

Total A = 700

Convert to % A

Calculate Total # a

(100 X 2) + (100 X 1)

Total a = 300

Convert to % a

Calculate TOTAL # A

(300 X 2) + (100 X 1)

Total A = 700

Convert to % A

700/1000 = 0.7

Calculate Total # a

(100 X 2) + (100 X 1)

Total a = 300

Convert to % a

300/1000 = 0.3

In the language of population genetics, p = % DOMINANT ALLELES

q = % RECESSIVE ALLELES

p q

Ladybug Generation 1

Ladybug Generation 2

In the language of population genetics, p = % DOMINANT ALLELES

q = % RECESSIVE ALLELES

p q

Ladybug Generation 1

0.5 0.5

Ladybug Generation 2

0.7 0.3

Class brainstorming - what might cause a shift in allele frequencies (% A/a or p/q)?

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

LARGE POPULATION

Genetic Drift: allele % fluctuations due to TOO SMALL SAMPLE - BOTTLENECK

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

LARGE POPULATION

NO MIGRATION

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

LARGE POPULATION

NO MIGRATION

NO MUTATIONS

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

LARGE POPULATION

NO MIGRATION

NO MUTATIONS

MATING RANDOM

Hardy-Weinberg (1908) predicted allele frequencies would NOT change if…

LARGE POPULATION

NO MIGRATION

NO MUTATIONS

MATING IS RANDOM

NO SELECTION FOR CERTAIN TRAITS

Predicting and Detecting Variation

For dom/rec traits, which is only genotype you know for certain based on

phenotype?

HW developed a useful predictive equation: p2 + 2pq + q2 = 1

Let’s say you want to predict the # carriers of a new recessive disease allele.

Math Calisthenics II

Epidemiology Data from Monmouth

aa = 1600/10,000

Calculate p

Calculate q Calculate p2 & 2pq

Let’s say you want to predict the # carriers of a new recessive disease allele.

Math Calisthenics II

Epidemiology Data from Monmouth

aa = 1600/10,000

Calculate p

Calculate q

q2 = 1600/10,000

= 0.16

= 0.4 = q

Calculate p2 & 2pq

Let’s say you want to predict the # carriers of a new recessive disease allele.

Math Calisthenics II

Epidemiology Data from Monmouth

aa = 1600/10,000

Calculate pp + q = 1… SO

1 - 0.4 = p0.6 = p

Calculate q

q2 = 1600/10,000

= 0.16

= 0.4 = q

Calculate p2 & 2pq

Let’s say you want to predict the # carriers of a new recessive disease allele.

Math Calisthenics II

Epidemiology Data from Monmouth

aa = 1600/10,000

Calculate pp + q = 1… SO

1 - 0.4 = p0.6 = p

Calculate q

q2 = 1600/10,000

= 0.16

= 0.4 = q

Calculate p2 & 2pq

p2 = (0.6)(0.6) = 0.36

2pq = 2(0.6)(0.4)

= 0.48

Check Work! Does p2 + 2pq + q2 = 1?What does this data mean???

Lab: Aside from disease/carrier status, why is knowing heterozygosity important?

Many alleles display

polymorphisms detectable at

DNA OR PROTEIN

LEVEL

Now consider sickle cell polymorphism…

Prokaryotes make protective nucleases called RESTRICTION ENZYMES (20.1-2)

e.g. DdeI cuts CTTAG - distinguishes hemoglobin alleles (Fig. 20.9)

In lab, you will explore protein gels of enzyme complexes to predict genotypes.

Consider that some enzymes are made of single proteins - MONOMERS

Hom/Dom Hom/Rec Het/Dom

1 BAND 1 BAND 2 BANDS

Others are made of multiple proteins - e.g. DIMERS, 2 FOLDED CHAINS

Hom/Dom Hom/Rec Het/Dom

1 BAND 1 BAND 3 BANDS

Population Genetics and Evolution

Do any populations meet HW conditions?RARELY AND NOT FOR LONG

Evolution: CHANGES in the genetic makeup of a population OVER TIME