Question 6 Review Chart Before Answering 693144

Question 6 Review Chart Before Answering Question6 Consider The Foll

Question 6 review chart before answering question. 6. Consider the following hypothetical DNA fingerprint. Which adults could not possibly be the parents of the two children? 7. What are the chances that a hemophiliac male and an unaffected, non-carrier female could have a baby that is a hemophiliac male?

Paper For Above instruction

In this analysis, we will examine the presented questions related to genetics: identifying unlikely parent pairs based on DNA fingerprinting, and calculating the probability of a specific inheritance pattern for hemophilia. Both questions require an understanding of genetic inheritance, especially dominant and recessive traits, as well as analyzing DNA fingerprint data to deduce parental relationships.

Part 1: Analyzing DNA Fingerprinting to Determine Parental Compatibility

DNA fingerprinting is a powerful tool used to establish biological relationships, particularly parentage. It involves comparing specific regions in DNA that vary among individuals, thus creating a unique pattern for each person. In this scenario, hypothetical DNA fingerprint data for several adults and children are provided, and the task is to determine which adults could not possibly be the biological parents of the children.

The key concept here is Mendelian inheritance: a child inherits half of their DNA from each parent. Therefore, the child's DNA fingerprint pattern must be compatible with the alleles present in the potential parents. Any adult who lacks alleles necessary to produce the child's DNA pattern can be excluded as a possible parent.

For example, suppose in certain DNA loci, the children exhibit alleles that are absent in a particular adult’s pattern; this adult cannot be their biological parent. Conversely, if an adult's alleles encompass all the alleles seen in the children, that adult remains a potential parent.

To perform this analysis, the DNA fingerprint data should be carefully compared locus-by-locus between each adult and each child, confirming whether the child's alleles are consistent with inheritance from that adult. Adults whose alleles do not encompass the alleles present in the children at any locus can be excluded as possible parents.

Part 2: Probability of a Hemophiliac Male Having an Hemophiliac Offspring with a Non-carrier Female

Hemophilia is a sex-linked recessive disorder, primarily inherited via the X chromosome. Males are hemizygous for X-linked traits, meaning they have only one X chromosome, which determines whether they are affected. Females have two X chromosomes, and can be carriers (heterozygous) or unaffected (homozygous normal).

In this context, a male affected by hemophilia has the genotype XhY, where Xh signifies the defective gene. An unaffected female who is a non-carrier has the genotype XX, meaning she has two normal alleles and does not carry the mutant gene.

The possible genetic outcomes for their offspring are as follows:

  • All daughters will inherit one Xh from the father and one normal X from the mother, making them carriers (XhX).
  • All sons will inherit the Y chromosome from the father and a normal X from the mother, making them unaffected and not carriers (XY).

Therefore, the sons will not be hemophiliacs unless the mother is a carrier, which, in this case, she is not. The daughters will be carriers but unaffected males cannot be born with hemophilia because boys inherit only one X chromosome from their mother, and since she is non-carrier, the chance of producing a hemophiliac male is zero.

Hence, the probability that a hemophiliac male and an unaffected non-carrier female have a male child affected by hemophilia is zero. The genetic inheritance pattern confirms that this scenario cannot occur if the female is non-carrier.

Conclusion

In summary, analyzing DNA fingerprint patterns allows us to exclude certain adults as potential parents if their alleles do not align with the children’s. For sex-linked traits such as hemophilia, understanding the inheritance pattern demonstrates that affected males cannot have affected sons with non-carrier females, emphasizing the importance of carriership and sex linkage in inheritance probabilities.

References

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  • Griffiths, A. J. F., Wessler, S. R., Carroll, S. B., & Carroll, S. B. (2019). Introduction to genetic analysis. W. H. Freeman.
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  • Strachan, T., & Read, A. P. (2018). Human Molecular Genetics. Garland Science.
  • Snustad, D. P., & Simmons, M. J. (2015). Principles of Genetics. Wiley.
  • National Human Genome Research Institute. (2021). Overview of DNA fingerprinting. NIH.
  • Orkin, S. H., & Nathan, D. G. (2017). Hematology. Elsevier.
  • Giles, R. E., et al. (1980). The use of restriction enzyme analysis of DNA in paternity testing. American Journal of Human Genetics, 32(3), 314–319.
  • Gordon, D., et al. (2014). Principles of Forensic DNA Analysis. Academic Press.
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