Simon Lin
Biology SL
Period 7
January 21, 2010
Biology Fly Lab
Background Information
Thomas Hunt Morgan, an American gene...
Dominant Allele
Parents: Wild eye + Lobe eye
Lw Lw
Lw Lw
Offspring 1: Lobe eye
ww Lw
Lw LL
Offspring 2: Lobe eye & Wild ey...
Recessive Allele
Parents: Wild eye + Purple eye
Wp Wp
Wp Wp
Offspring 1: Wild eye
WW Wp
Wp pp
Offspring 2: Wild eye & Purp...
Dominant Sex-Linked Allele
Parents: Male: Bar eye + Female: Wild eye
XWXB XWY
XWXB XWY
Offspring 1: Male: Wild eye Female:...
Recessive Sex-Linked Allele
Parents: Male: Tan Body + Female: Wild Body
XTXW XWY
XTXW XWY
Offspring 1: Male: Wild Body Fem...
Dominant Lethal Allele
Parents: Male: Wild Wings + Female: Curly Wings
WW WW
WC WC
Offspring 1: Wild Wings & Curly Wings
W...
dominant lethal allele the ratio would be 3:1. Only 75% of the offspring will like to
survive. Therefore dominant lethal a...
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Fly Lab

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Fly Lab

  1. 1. Simon Lin Biology SL Period 7 January 21, 2010 Biology Fly Lab Background Information Thomas Hunt Morgan, an American geneticist and embryologist. He was in Columbia University and founder of the Fly Room. His experiments are based of using fruit flies, called Drosophila melanogaster, and being able to demonstrate that genes are carried on chromosomes to the next generation. Morgan bred a white-eyed male fly with a red-eyed female. All the offspring produced both male and female, which both had red eyes. Later he bred the offspring male and female, which resulted that some offspring ended up with red eyes and some with white eyes. All of the flies with white eyes were males. In conclusion he found out the first evidence of a sex-linked recessive trait. By using his studies and experiment support, he won the Nobel Prize in Medicine in 1933. Introduction Throughout the lab, the experiments are to be done online. The online lab will provide the different types of fruit flies that are available for the experiment. The purpose of the lab is to mate different flies with the “wild type”, which is known as the normal flies, and find a mate that traits are inherited. The types that are to be found are: Dominant allele Recessive allele Dominant sex-linked allele Recessive sex-linked allele Dominant lethal allele.
  2. 2. Dominant Allele Parents: Wild eye + Lobe eye Lw Lw Lw Lw Offspring 1: Lobe eye ww Lw Lw LL Offspring 2: Lobe eye & Wild eye Conclusion Two different types of fruit fly, lobed-eye fruit fly and wild fruit fly. To be a dominant allele, the parents must be homozygous, nothing mixed to see the result. In which when the parents mated, the 1st generation only showed lobed-eye fruit flies meaning that the allele of lobed eye dominates over wild fruit flies. However before both of the flies were homozygous, but when both of it mate, the offspring it creates are heterozygous. When the 1st offspring mated together, it’ll create 2nd offspring of 25% Wild fruit flies, and 75% Lobe-eye fruit flies. It shows that when the two heterozygous fruit flies mated most of it will be lobe-eye but some will come back to normal, which it was hidden away in the 1st offspring. Simply when the trait is dominant it will appear more than the other trait. W W L L w L w L Phenotype: Lobe Genotype: 100% Lobe (Heterozygous) Chi-Square Analysis = 0.000000 Observed = 984/1000 Hypothesis = 1.00000 Degree of freedom = 0 Level of Significance = 1.00000 Do Not Reject You Hypothesis Phenotype: Lobe, Wild Genotype: 50% Lobe (Heterozygous) 25% Lobe (Homozygous) 25% Wild (Homozygous) Chi-Square Analysis = 0.1992 Observed = W: 247/1000 L: 717/1000 Hypothesis = W: 1 L: 3 Degree of freedom = 1 Level of Significance = 0.6554 Do Not Reject You Hypothesis
  3. 3. Recessive Allele Parents: Wild eye + Purple eye Wp Wp Wp Wp Offspring 1: Wild eye WW Wp Wp pp Offspring 2: Wild eye & Purple eye Conclusion Two different types of fruit fly, Wild eye fruit fly and purple eye fruit fly. To be a recessive allele, the parents must be homozygous, nothing mixed to see the results. In which when the parents mated, 1st generation only showed wild eye fruit flies meaning that the allele of purple eyes is weaker than the wild eyes, recessive. If purple trait is recessive it will definitely show in the 2nd generation of the offspring. In which the data has shown that purple eye reappeared in the 2nd offspring, showing that during the 1st offspring the trait was dominated by Wild eye. Therefore when the 1st offspring both heterozygous mated it will create some purple eye fruit flies in their next generation. Simply when the trait is recessive it won’t show in the 1st generation, but it will show in the 2nd generation of offspring. W W P P W p p W Phenotype: Wild Genotype: 100% Wild (Heterozygous) Chi-Square Analysis = 0.000000 Observed = 1035/1000 Hypothesis = 1.00000 Degree of freedom = 0 Level of Significance = 1.00000 Do Not Reject You Hypothesis Phenotype: Wild, Purple Genotype: 50% Wild (Heterozygous) 25% Wild (Homozygous) 25% Purple (Homozygous) Chi-Square Analysis = 0.6133 Observed = W: 743 Purple: 262 Hypothesis = W: 3 Purple: 1 Degree of freedom = 1 Level of Significance = 0.4336 Do Not Reject You Hypothesis
  4. 4. Dominant Sex-Linked Allele Parents: Male: Bar eye + Female: Wild eye XWXB XWY XWXB XWY Offspring 1: Male: Wild eye Female: Bar eye XWXW XWY XWXB XBY Offspring 2: Male: Wild & Bar eye Female: Wild & Bar eye Conclusion The male fruit fly has the trait of Bar eye, and the female fruit fly has the trait of wild eye. To show that bar eye is a dominant sex-link trait, the female has to be a bar eye when it’s a heterozygous fruit fly and has a trait of bar eye in its gene. As shown in offspring 1, the female will all inherit the trait of bar eye from due the fact that male fruit fly has only the bar eye gene. That will be one proof shown. Then in the 2nd generation of offspring, half of the male and female will be bar eye since there whenever there is a bar eye allele it will dominate over the other trait. Therefore Bar eye is a dominant sex- linked trait. XB Y XW XW XW Y XW XB Phenotype: Male: Wild Female: Bar Genotype: Male: 100% Wild (Homozygous) Female: 100% Bar (Heterozygous) Chi-Square Analysis = 0.2243 Observed = Female: 484/1000 Male: 509/1000 Hypothesis = Female: 1.0000 Male: 1.0000 Degree of freedom = 1 Level of Significance = 0.6358 Do Not Reject You Hypothesis Phenotype: Male & Female: Wild & Bar Genotype: Male: 50% Wild & 50% Bar (Homozygous) Female: 50% Bar (Heterozygous) 50% Wild (Homozygous) Chi-Square Analysis = 6.3077 Observed = Female W: 234/1000 B: 272/1000 Male W: 286/1000 B: 248/1000 Hypothesis = Female: 1.0000 Male: 1.0000 Degree of freedom = 3 Level of Significance = 0.0976 Do Not Reject You Hypothesis
  5. 5. Recessive Sex-Linked Allele Parents: Male: Tan Body + Female: Wild Body XTXW XWY XTXW XWY Offspring 1: Male: Wild Body Female: Wild Body XWXW XWY XWXT XTY Offspring 2: Male: Wild & Tan Body Female: Wild Body Conclusion The male fruit fly eye has the Tan body allele, and the female fruit fly has the wild body allele. To show that Tan body is a recessive sex-linked trait, the female will have to still be wild when there is a Tan body allele in it. As shown in offspring 1, when the female offspring inherited the allele of the Tan body nothing showed up, which means that wild body is dominated over the recessive Tan body. Then Looking at the Offspring 2, the same thing occurred with the female fruit fly, the tan body trait did not show up again. However it showed up for the male since male only need 1 allele to determine how it is going to be. Therefore Tan body is a recessive sex-linked trait. XW XW XT Y YXW XW XT Phenotype: Male: Wild Female: Wild Genotype: Male: 100% Wild (Homozygous) Female: 100% Wild (Heterozygous) Chi-Square Analysis = 0.5392 Observed = Female: 479/1000 Male: 502/1000 Hypothesis = Female: 1.0000 Male: 1.0000 Degree of freedom = 1 Level of Significance = 0.4627 Do Not Reject You Hypothesis Phenotype: Male: Tan & Wild Female: Wild Genotype: Male: 50% Wild & 50% Tan (Homozygous) Female: Wild 50% (Homozygous) 50% (Heterozygous) Chi-Square Analysis = 4.6103 Observed = Female W: 530/1000 Male W: 302/1000 B: 256/1000 Hypothesis = Female: 2.0000 Male: 1.000 + 1.000 Degree of freedom = 2 Level of Significance = 0.0997 Do Not Reject You Hypothesis
  6. 6. Dominant Lethal Allele Parents: Male: Wild Wings + Female: Curly Wings WW WW WC WC Offspring 1: Wild Wings & Curly Wings WW WC WC CC Offspring 2: Wild Wings Curly Wings Conclusion The two different types of fruit flies, Curly wings fruit fly and Wild wings fruit fly, shows how dominant lethal allele works. Dominant lethal alleles can’t survive being homozygous, which in this case curly wings fruit fly can never be homozygous. Also, being dominant lethal allele, the trait/allele will dominate over the other trait. Offspring 1, A heterozygous Curly wings mated with a homozygous wild wings it creates half Wild half Curly showing that Curly wings dominate over Wild wings. Dominant lethal allele will show by the generation of offspring 2. Since the 2 mated fruit flies are Curly wing heterozygous, it will one point produce a homozygous curly wing. However it will never survive so as the data show that the ratio between curly to wild is only 2:1, if its not a W W W C W W C C Phenotype: Curly & Wild Genotype: 50% Wild (Homozygous) 50% Curly (Heterozygous) Chi-Square Analysis = 0.2312 Observed = Wild: 494 Curly: 479 Hypothesis = Wild: 1.0000 Curly: 1.0000 Degree of freedom = 1 Level of Significance = 0.6306 Do Not Reject You Hypothesis Phenotype: Curly & Wild Genotype: 25% Wild (Homozygous) 50% Curly (Heterozygous) Chi-Square Analysis = 0.1969 Observed = Wild: 332 Curly: 684 Hypothesis = Wild: 1.0000 Curly: 2.0000 Degree of freedom = 1 Level of Significance = 0.6573 Do Not Reject You Hypothesis
  7. 7. dominant lethal allele the ratio would be 3:1. Only 75% of the offspring will like to survive. Therefore dominant lethal allele will only be shown by the 2nd generation when mating only curly wing fruit flies, and curly wings is a dominant lethal allele.

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