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Evaluating generations of fruit flies for inherited characteristics.

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Introduction

P1 Generation: 1. 4 : 0 Large wing vestigial wing The above ratio is phenotypic; as the predicted outcome of the F1 generation is 100% heterozygous, meaning they all have a dominant allele (A) and a recessive allele (a) for wing size, all the offspring?s show up to have large wings and none have vestigial wings. The female parent possesses large wings, it is assumed they are homozygous dominant (AA; A indicates large wing size); whereas, the male parent possesses vestigial wings, therefore they are homozygous recessive (aa; a indicates vestigial wing size) due to vestigial wings being recessive to large wings. Since the female parent has homozygous dominant alleles (AA) and the male parent has homozygous recessive alleles (aa), all offspring inherit one dominant allele (A) from the female parent and a recessive allele (a) from the male parent, resulting in heterozygous (Aa) alleles with large wings. The class results for the F1 generation states 129:24 (Large wing: vestigial wing) and this result is relatively close to the predicted ratio of 4:0, the results obtained did not quite match our prediction. However, it could be said that the vestigial wings are small in number when compared to large wings, therefore they could be ignored. F1 Generation: 1. 3 : 1 Large wing vestigial wing The above ratio is phenotypic; as the predicted outcome of the F2 generation is 75% Large wing and 25% vestigial wing, meaning 75% of them possess at least one dominant allele (A) ...read more.

Middle

At the same time, 8/16 (=1/2) of the offspring inherit one white eye allele (Xr) from the mother fly and a red eye allele (XR) from the father fly, resulting them to be female offspring (due to two copies of the X chromosome) with red eyes (due to red eyes being dominant to white eyes in fruit flies; only one copy of the red eye (XR) is sufficient to show up as red coloured eye). The other half- 8/16- inherit one white eye allele (Xr) from the mother fly and a Y chromosome from the father fly, resulting them to be male (due to one X chromosome and one Y chromosome) and white eyed (because the eye colour is sex linked, and is only carried by the X chromosome, also there is only one copy of the white eye allele). Overall, half the offspring are male, they have white eyes and brown bodies (XrY-Bb); half the offspring are female, they have red eyes and brown bodies (XRXr Bb). The class results for the F1 generation states 3:11:26:6:35:8:2:0 (Red-eye, brown body, male: Red-eye, Black body, male: White-eye, Brown body, male: White-eye, black body, male: Red-eye, brown body, female: Red-eye, Black body, female: White-eye, Brown body, female: White-eye, black body, female). The results obtained do not accurately match our prediction which was a ratio of 1:1 (White-eye, Brown body, male: Red-eye, brown body, female). ...read more.

Conclusion

from the father fly, resulting them to be red eyed (XRXr) (as red eye alleles are dominant to white eye alleles, even one copy is sufficient to show up as red eye). 1. The class results for the F2 generation states 40:20:31:21:55:20:40:17 (Red eye, Brown body, male: red eye, Black body, male: White eye, Brown body, male: white eye, Black Body, male: red eye, brown body, female: red eye, black body, female: White eye, brown body, female: white eye, black body, female). The results obtained clearly do not accurately match our prediction which was a ratio of 3: 1: 3: 1: 3: 1: 3: 1 (Red eye, Brown body, male: red eye, Black body, male: White eye, Brown body, male: white eye, Black Body, male: red eye, brown body, female: red eye, black body, female: White eye, brown body, female: white eye, black body, female). However, it could be said that the red eye, brown body and male individuals share the same result as white eye, brown body and female individuals, which is 40, the ratio for these two is 3:3 (=1:1) from the findings in the Punnett square and the observed ratio is 40:40 (=1:1). Another slightly accurate result is the red eye, black body and male individuals share the same result as the red eye, black body and female individuals which is 20:20 (=1:1); and our predicted ratio was 1:1 between these two possibilities. This shows that some results do match our prediction, when compared with specific results; however, in general it is not quite accurate. ...read more.

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