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The main objective of this experiment is to investigate dihybrid inheritance and understand the basic genetic and the process of division

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Introduction

The expected and observed results of the experiment (P18.1b) Aim: The main objective of this experiment is to investigate dihybrid inheritance and understand the basic genetic and the process of division and also to compare expected and observed results between test tube A and B. Procedure * Two breading tubes are set: * Breading tube A- 6 males (black body) and 6 females (vestigal wings) * Breading tube B- 6males (vestigal) and 6 females (black body) * Both vestigal and black body flies are put in separate tubes to ensure they are not sexually linked. * After flies are bread they are put to sleep by substance called fly-nap. This will put them to sleep, allowing me to separate and count them. OBSERVED RESULTS TUBE A * MALE = BLACK BODIED, NORMAL WINGS (bbTT) * FEMALE = NORMAL BODY, VESTIGAL WINGS (BBtt) Parent's bbTT X BBtt F1 12 males: all normal body, normal wings 14females: all normal body, normal wings F2 8 males: 10 females - normal body, normal wings 4 males: 3 females - normal body, vestigal wings 2 males: 5 females - normal wings, black body 1 male: 1 female - ebony body, vestigal wings TUBE B * MALE = NORMAL BODY, VESTIGAL WINGS (BBtt) * FEMALE = BLACK BODY, NORMAL WINGS (bbTT) Parents BBtt x bbTT F1 15 males: all normal body, normal wings 13 females: all normal body, normal wings F2 4 males: 5 females - normal body, normal wings 2 males: 2 females - normal body, vestigal wings ...read more.

Middle

Possible reasons for difference from expected result could be due to an error done during my experiment. The other reason could be during meiosis, though, my results for male test tube A differed slightly from expected result, but it still followed Mendel's 2nd law of inheritance (3:1 ratio). Males in 2nd tube 4 Normal body, Normal wings 2 Normal body, vestigal wings 3 black body, normal wings 0 black body, normal wings Expected 9: normal body, normal wings 3: normal body, vestigal wings 3: black body, normal wings 1: black body, vestigal Difference The expected values from my experiment had large amount of difference from the 9:3:3:1 ration. Possible reasons for difference from expected result could be due to an error done during my experiment. The other reason could be during meiosis, pairs of homologues chromosomes assemble themselves randomly on the equator of the spindle during metaphase 1 of meiosis, though each pair has the same general features, they differ in the detail of these features. Another possibility could be, during prophase 1 of meiosis, equal portions of homologous chromosomes may be exchanged to produce new genetic combinations and the separation of linked genes The observed result does not match with Mendel's 2nd law of inheritance (3:1 ratio). Females in tube A 10 normal body, normal wings 3 normal body, vestigal wings 5 black body, normal wings 1 black body, vestigal wings Expected 9: normal body, normal wings 3: normal body, vestigal wings 3: black body, normal wings 1: black body, vestigal Difference The expected values from my experiment had tiny amount of difference from the 9:3:3:1 ration. ...read more.

Conclusion

De novo mutations are thought to be the possible cause of genetic disorders in which a child is affect genetic disorder but has no history of family disorders. Mutations that occur in parents DNA during parent life time could have been acquired through environment changes such as ultraviolet radiation from sun, and mistakes in gene copy during cell division. Gene mutation acquired from cells other than sperm or eggs cells can not be passed on to next generation. Mutation can also occur in a single cell within an embryo, when the cell is dividing during growth and development; the individual will have genes cells and genes with no genetic change. This process is called mosacism. Genetic changes that occur in more than 1% of population are called polymorphisms. There are so common that there are considered as gene variation in DNA. Polymorphisms are the cause of differences such as; eye colour, hair colour and blood type. They have no known negative effects on an individual but other types of mutation such as de novo mutation or heredity mutation can influence risk of developing disorders. Gene mutation can cause alteration during the making of protein and ultimately, cause the protein to malfunction. Proteins are the main component in body tissue and help build, repair muscles, tissues and increase strength of an individual; malfunction of the protein could cause medical disorders such as cystic fibrosis. Bibliographies Biological Sciences' by D. J. Taylor (Author), N. P. O. Green (Author), G. W. Stout (Author) http://www.biology-online.org/biology_articles.htm http://www.biology.arizona.edu/DEFAULT.html ?? ?? ?? ?? Kwame Adu-Akyeampong Page 1 10/30/2009 Kwame Adu-Akyeampong Page 1 10/30/2009 ...read more.

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