Since heterozygous individuals have a enhanced resistance to malaria, then that means that the homozygous dominant and recessive individuals are more susceptive to malaria, thus they are more likely to die. Meaning that, the heterozygous population would be greater than that of the homozygous population. Thus there is high probability that children come from heterozygous parents, and if heterozygous individuals have children, then the probability that the child would carry the gene is 75%, but only a 25% chance that they will have the sickle-cell disorder.
Part III Hemophilia
- Draw the pedigree in your notebook. Write in the genotype for each individual.
- Why do more males have hemophilia than females?
More males have hemophilia than females because hemophilia is a sex-linked recessive allele, and in females, the hemophilia allele can be masked by a normal blood allele since females have two X chromosomes. However males only have one X chromosome, and thus, if they carry the hemophilia allele, they cannot mask it. Meaning if males inherit the hemophilia gene, they will 100% show the disorder. However, if females inherit the hemophilia gene, they will only have a 50% chance of showing the disorder.
- Explain how the female (III-3) can have hemophilia.
Since a female has two X chromosomes and has to get one from each parent, then the father can only give his hemophilic X chromosome and the mother can either give her hemophilic X chromosome or her normal blood X chromosome. In this case, the mother gave the daughter a hemophilic X chromosome.
Part IVa Problems
- How is this trait inherited?
This trait is inherited by an autosomal dominant allele
- Draw the pedigree in your notebook and write in the genotype for each individual.
Part IVb Problems
- How is this trait inherited?
This trait is inherited by a sex-linked recessive allele
- Draw the pedigree in your notebook and write in the genotype for each individual.
Analysis and Interpretation
- Could you determine the genotype of each individual in this Activity?
I could not determine the genotype of each individual in this activity because some of the pedigrees did not indicate which individuals were carriers (heterozygous) and which individuals were not infected. Thus, in such a case, a certain individual would have 50% chance of being a carrier and 50% chance of being not infected.
- Give an example of an individual where you could work out only the probability of a particular genotype, and calculate that probability.
In the above example, individual II-2 has a 50-50 percent chance of being a carrier or of being non infected, because the genotypes of her parents are not identified, and she herself in does not display the disorder, thus she has a 50-50 percent chance.
- Suppose that you discovered that you and your spouse are both heterozygous for a lethal recessive gene. Would you have children? Explain. Would you decision change if the trait involved was debilitating but not lethal? Explain.
I would have children because there’s only a 25% chance that my child would die, thus 75% that they would live and have a healthy life. If the trait was debilitating but not lethal, then I would definitely have children because they are 100% chance of not dying from this trait, and only 25% chance of showing it. Thus its most probable that my child would come out healthy, and even if it doesn’t, the love that my wife and I provide should be able to overcome the disability
- Many genetic diseases extract a high cost in terms of health care dollars. Since medicare is funded by government funds, should the government be allowed to legislate who may and who may not have children? Defend your position.
No, they shouldn’t have the power to decide because if the government did, the people carrying a disease or showing a disease would not be allowed to pass on their genes, thus the gene pool of the human race would be reduced, thus there is less variation, and a higher chance of more diseases developing. Eventually, everyone would be infected and the human race would be wiped out.
CONCLUSION AND EVALUATION
Conclusion: Through the findings of this lab, I discovered that pedigrees can be used to determine the probability of a trait appearing in the next generation and can be used help dictate whether a couple would want to have children or not.
Evaluation:
