Introduction
Our class has been learning about genetics and DNA, particularly, the make up, and the outcome. When learning about most things, the way to learn about it more effectively, is to actually do it and be involved in a similar process. In this experiment the organisms our class used were fruit flies. We attempted to find out if, when pairing organism with certain phenotypes, and breeding them, what the offspring would result in. If there would be any inheritance pattern(s) (dominant/ Recessive)with the outcome of the offspring.
Phenotypes
An organism's appearance or other detectable characteristics that results from the organism's genotype and the environment.
In this experiment there were three different phenotypes-
vestigial- consists of a fruit fly having misshaped wings and red eyes.
Wild type- consists of a fruit fly having red eyes and normal wings.
White eyes- consists of a fruit fly having white eyes and normal wings.
Life Cycle Log
02-27-06 ~ the flies expanded into new cultures.
03-02-06 ~ today there was no sign of larvae, the medium is kind of dry so we added water to the vials.
03-03-06 ~ we saw larvae today, the little black heads were moving.
03-06-06 ~ It was easier to see the larvae today, because they were much darker and also they were moving a little bit faster. We saw about 15 pupae also.
03-07-06 ~ you can start to see black dots inside the larva and on the sides there's a lot more pupae.
03- 09-06 ~ still more pupae developing, you can see more larvae moving in the medium.
03-10-06 ~ The medium decreased, the amount of larvae increased , pupae are forming and they are about ready to hatch.
03-13-06 ~ There are a lot of pupae and a lot of the grown up flies, some are hatching at the bottom you can see their feet. still a little bit of larvae.
P-CROSS
03-16-06 ~ Two flies have died in vail #2 ,4 alive in vial #1
03-20-06 ~ The medium began to turn brown
03-21-06 ~ medium is really showing brownness, vial #2 all the flies have died
03-23-06 ~medium in vial #1 shows a little less brown in vial #2 they're are a few dead flies and 5 flies are still alive. In vial 1 there are 6 alive.
03-24-06 ~ In vial 2 there is one fly with only one wing. larvae formed and trying to get out of medium. larvae crawling on the sides. in vial 1 larvae formed and are on the walls.
03-27-06 ~Vial 2 has a lot more pupae. the medium has a hole in the center. Vial 1 has pupae and some of them are darker than the others
03-28-06 ~In vial 1 we have flies but there are still pupae, left in vial 2 the pupae haven't hatched yet.
03-30-06 ~In vial 1 there are more flies and they are a lot more active in vial 2 are also active.
03-31-06 ~ the medium is getting smaller, there are still larvae and some pupae left.
04-03-06 ~In vial 1 there are a lot of dead flies but in vial 2 the flies look fine
04-06-06 ~ In vial 1 all the flies were dead, we had to put in more flies
04-07-06~ the flies didn't wake up from the fly nap from yesterday and we have pupa in both vials and we emptied out the old flies
04-17-06 ~Vial 2 lot of flies alive larva is visible on the sides of vial. flies with red eyes are present, larvae are in medium.Vial 1 not as much flies alive. flies with red eyes present. some larvae on sides of dead flies in medium.
4-20-06 ~flies in vial 1 not moving, more flies continue to hatch in vial 2
4-21-06 ~ in vial 2 there were a couple flies larva - moving around misshaped, in vial 1 no flies all got stuck in medium larva in vial 1
04-24-06 ~ in vial 1 there were 36 flies all were red eyes except for 1. there is larva on side of vial medium goes from a beige color to a darker brown . In vial 2 there were 12 flies all were red eyed medium is smaller than vial 2's.color again goes from beige to brown larvae is on sides and moving
04-25-06 ~ in vial 1 there's still larva on the sides. Quite a few flies hatched medium is still the same. in vial 2 less flies hatched than in vial 1 medium is smaller than in vial 1 medium is smaller than vial 1 and is a little more dark brown.
Sexing the Flies
The way we determined between the flies' sexes when either choosing them to breed, or when documenting information after mating, is we examined their abdomen. Male fruit flies' abdomen is darker than that of a female. We also looked at their lower abdomen. In males, their abdomen are usually more rounded than a female's.
F1 predictions
Hypothesis 1:
If vestigial (Vg) is Autosomal dominant then: phenotype % will be 100% vestigial and genotype % will be 100% Vg+ heterozygous
| Vg | Vg | |
| + | Vg+ | Vg+ |
| + | Vg+ | Vg+ |
Hypothesis 2:
If vestigial (Vg) is Autosomal recessive then: phenotype % will be 100% wild and genotype % will be 100% +Vg, 100% heterozygous
| + | + | |
| Vg | +,Vg | +Vg |
| Vg | +Vg | +Vg |
Hypothesis 3:
If vestigial (xvg) is sex-linked and dominant and the mutation is on the female, then phenotype % will be 50% vestigial female and 50% vestigial male. And genotype % will be 50% XvgX+ female heterozygous and 50% xvgy male.
| x+ | y | |
| xvg | x+xvg | yxvg |
| xvg | x+xvg | yxvg |
If vestigial (xvg) is sex-linked and dominant and the mutation is on the male, then phenotype % will be 50% vestigial female and 50% wild male. And genotype % will be 50% XvgX+ female heterozygous and 50% male.
| x + | x+ | |
| xvg | x+xvg | x+xvg |
| y | x+y | x+y |
Hypothesis 4:
If vestigial (vg) is sex linked recessive and the mutation is on the female, then phenotype % will be 50% wild female and 50% vestigial male. And genotype % will be 50% X+Xvg female heterozygous and 50% xvgy male.
| xvg | xvg | |
| x+ | xvgx+ | xvgx+ |
| y | xvgy | xvgy |
If vestigial (vg) is sex-linked recessive and the mutation is on the male, then phenotype % will be 50% wild female and 50% wild male. And genotype % will be 50% X+y male and 50% X+Xvg female heterozygous.
| xvg | y | |
| x+ | xvgx+ | yx+ |
| x+ | xvgx+ | yx+ |
F1 Outcomes
Vial 1 P cross= vg female X + male
F1 male phenotype = + male
Vail 1 P cross = vg X + male
F1 female phenotype = + female
Vial 2 P cross = + female X vg male
F1 male phenotype = + male
Vail 2 P cross = + female X vg male
F1 female phenotype = + female
In both Vial 1 and 2 the male and female flies came out wild.
F2 Predictions
Hypothesis 1 (vial 1):
If F1 generation wild male (genotype +vg) crosses with F1 wild female (genotype +vg) then phenotype % in F2 offspring will be 75% wild and 25% vestigial. And genotype % in F2 offspring will be 25% homozygous dominant ++, 25% homozygous recessive vgvg, and 50% heterozygous dominant +vg.
| + | vg | |
| + | ++ | vg+ |
| vg | +vg | vgvg |
Hypothesis 2 (vial 2):
If F1 generation wild male (genotype +vg) crosses with F1 wild female (genotype +vg) then phenotype % in F2 offspring will be 75% wild and 25% vestigial. And genotype % in F2 offspring will be 25% homozygous dominant ++, 25% homozygous recessive vgvg, and 50% heterozygous dominant +vg.
| + | vg | |
| + | ++ | vg+ |
| vg | +vg | vgvg |
F2 Final count
| Date F2 Counted | Female wild + | Male Wild + | Male Vg | Female Vg |
| 4-17-06 | 0 | 3 | 0 | 0 |
| 4-21-06 | 0 | 0 | 0 | 0 |
| 4-24-06 | 19 | 16 | 1 | 0 |
| 4-25-06 | 14 | 21 | 0 | 0 |
| Overall Total from Vial 1 74 | Total female + 33 | Total male + 40 | Total female 1 | Total male 0 |
| DateF2 counted | Female wild+ | Male wild + | Male Vg | Female Vg |
| 4-17-06 | 12 | 9 | 0 | 0 |
| 4-21-06 | 4 | 7 | 0 | 0 |
| 4-24-06 | 5 | 6 | 0 | 0 |
| 4-25-06 | 9 | 13 | 0 | 0 |
| Overall Total From Vial 2 64 | Total female + 29 | total male + 35 | total Female 0 | total Male 0 |
Conclusion
The hypothesis for this experiment was if the mutation vestigial is autosomal recessive in the P generation, then by F2 generation the expected phenotype ratio is 3:1. But when looking at the actual results, it said different. Our hypothesis was not entirely incorrect, but none the less off. There was 31-33% error in the expectation of F2 wild flies. While there was a 95-100% error in F2 vestigial flies. A factor that is believed to have been a reason for this high % error, is that when during the process of transferring the flies into new vial to be napped, many of the flies got stuck in the medium, (which could have been vestigial). A way to have avoided this problem, could have been to lay the vials on their sides when transferring them, or napping them.
Although, due to the 'flies getting stuck in the medium' issue , there is a lack of data to prove our initial hypothesis. We believe that if the experiment were to have continued the results would have shown, that vestigial is a recessive trait. Which in our F1 predictions we predicted that wild would come out dominant every time, and in that we were correct.
With this, a new question, along with a new hypothesis has been conducted. Q: Which flies get stuck easier in the medium? Hypothesis: If there are flies stuck in the medium, the flies are vestigial.
Eulogy
R . I. P
O.D.F
old dirty flies
Passed on, on this day of
Thursday, March 23rd, 2006
see you when we get there!
