Genetics Of Organisms

Genetics of Organisms Chao Xu

The weeks long fly lab Introduction: The fruit fly are organism have short life cycle. The short life cycle allows study for genetics takes place easily. Procedure: 1. Obtain a vial of wild type flies, record their type. 2. Obtain few of each sex and record the frequency of each trait. 3. Put the flies into a vial with food and let them complete their life cycle 4. When eggs are laid, take out the flies from the vial. 5. When larva turns into flies, take them out from the vial and record the frequency of each trait and their sex. Result: F2 Generation Phenotype Red Normal Wing Red Vestigial wing Sepia Normal Wing Sepia Vestigial wing Total

Female 47 12 8 3 70

Male 54 29 15 5 103

Total 101 41 23 8 173

Discussion: The hypothesis for this cross is sepia eye vestigial wing both are non-sex linked recessive trait. Phenotype Observed Expected (o-e) (o-e)^2 (o-e)^2/e Red Normal 54 49 -5 25 25/49 Wing male Red Normal 47 49 2 4 4/49 Wing female Red 29 16 13 169 169/16 Vestigial wing male Red 12 16 4 16 16/16 Vestigial wing female Sepia 15 16 1 1 1/16 Normal Wing male Sepia 8 16 8 64 64/16 Normal Wing female Sepia 5 5 0 0 0/5 Vestigial wing male

Sepia Vestigial wing female

3

5

2

4

4/5

Chi-square 289 And the chi-square shows it’s wrong. The new hypothesis could be better. Which is vestigial wing and Sepia eye is sex-linked trait Phenotype Observed Expected (o-e) (o-e)^2 (o-e)^2/e Red Normal 54 49 -5 25 25/49 Wing male Red Normal 47 49 2 4 4/49 Wing female Red 29 22 8 64 64/21 Vestigial wing male Red 12 11 1 1 1/11 Vestigial wing female Sepia 15 21 6 36 36/21 Normal Wing male Sepia 8 11 3 9 9/11 Normal Wing female Sepia 5 6 1 0 1/6 Vestigial wing male Sepia 3 3 0 0 0/3 Vestigial wing female Chi-square 63 This makes Chi-square lower to 63, it is still to large. 1. Female of the parental generation have to be virgins so there will be nothing born with the genes outside the assigned males’ gene pool. 2. it’s not necessary to isolate virgin females for F1 because males all have the same genotype 3. The adult flies removed from the vials because those adult flies can mate with next generation and create a new hybrid.

Statistical analysis section Phenotpye Green Albino

Genotype GG or Gg gg Total

o 72 12 84

E 63 21 81

o-e 9 9

Phenotype Green Albino

O 72 12

E 63 21

o-e 9 9

(o-e)^2 81 81 Chi-square

(o-e)^2/e 81/63 81/21 5.1428

Practice problem a. The genotype of F1 is Ww b. The hypothesis: The Ww result intermediate-length wins, WW result long wings, ww result short wings Phenotype O E o-e (o-e)^2 (o-e)^2/e WW 230 250 20 400 400/250 Ww 510 500 10 100 100/500 ww 260 250 10 100 100/250 Chi-square 2.2 i. 1. Degree of freedom = 2 2. Chi-square = 2.2 3. Probability = 0.05 ii. According to Chi-square, this hypothesis can be accepted, 95% of time this hypothesis will be true with the data. Conclusion: The vestigial wing and sepia eye is most likely sex-linked recessive traits. But the Chisquare value is too large, the hypothesis should be rejected. The data could have flawed because male population are 30% more than female population. This flaw can be caused by fail to identify the sex of a fly.

Transpiration Chao Xu

Introduction: Transpiration is the lose of water from plant leaf surface. It is caused by low water potential outside the leafs that draws the water from the leafs. Procedure: 1. Wrap the 4 plants in plastic bags and weight each one of them 2. Each one of the plant will be assigned in a group. fan, light, room and moist. 3. Wait each one of the plants each day and record data 4. Calculate the surface area of each plant's leaf and record data Data: Condition

Day 1 mass (g)

Day 2 mass (g)

Day 4 mass (g)

% of change in mass

Surface area cm^2

Room

62.8

62.4

60.2

-4.14

3.2

Light

62.6

62.0

58.0

-7.35

9.1

Mist

50.8

51.6

50.9

.2

13.5

Fan

59.7

59.1

55.44

-7.14

2.7

Discussion: 1. Room loses .0225ml/min/m^2 of water Light loses .876ml/min/m^2 of water Mist gain .013ml/min/m^2 of water Fan loses 2.765ml/min/m^2 of water 2. Condition Effect

Explanation of Effect

Room

Nothing

It is the control

Fan

Loses water

fan allow evaporation faster by keep recycling the air

Light

Loses water

Light allows photosynthesis it opens stomata

Mist

Gain water

The air water potential is larger than the leaf's water potential

3. Water potential allows the leaves to have tension. water in the soil with higher potential will move up through the plant and move out into the air because air have lower water potential 4. Closed stomata will stop losing too much water and let the leaf dry out. The disadvantage can be stop the gas exchange and photosynthesis productivity 5. The plants reduce water loss by close their stomata by having two guard cells that form a opening shape only if there is enough water. 6. The leaf surface area is what creates the water loss. Calculate the surface area can

show the ratio between the losses of water per unit surface area. Conclusion: The change in water potential allows water to transpiration from the plants, the opening of stomata allows more water to be lost to transpiration because it creates more surface area. The control plant in room condition changes in its mass could be because the room condition is not the optimal condition for the plant.