Start reviewing and responding to the postings of your classmates as early in the week as possible. Respond to all of the initial postings from your peers in your discussion group on different days of the week.

Peer 1

Punnett square is a graphical representation of genotype odd resulting from the genetic crossing of a particular type.  The chart representation of possible offspring is essential in predicting traits, and this is achieved by analyzing the composition of the gene. According to R et al. (2018), Although the Punnett square is a convenient tool for genetic prediction, it has limitations in complex genetic inheritance. Significantly, the Punnett square is limited when predicting genotype in the scenario where two traits are inherited together or in the situation where two genes are linked (Lockhart, 2018). On the other hand, multiple genes can be used to determine a single trait, and therefore, the punnet square is limited in predicting offspring’s phenotype.  According to R et al. (2018), Hemophilia either occurs due to spontaneous mutation or inherited.  In the case given, the mother has a recessive allele(hemophilia) and a dominant allele. 

Odd of female offspring developing hemophilia

While mothers without hemophilia can transmit X chromosome with mutation, the female can receive a normal X chromosome from the father who is not affected by hemophilia.  That being the case, all the daughters will not have hemophilia although they inherit the X chromosome from the father. 

Odd of female offspring being hemophilia carrier 

Just like the mother, who is, in this case, a hemophilia carrier, there is a 50% chance that offspring will be a carrier.

Odd of male offspring  developing hemophilia 

In this case, the male offspring inherit the Y chromosomes from his father and the mother’s X chromosomes.  That being the case, the son can inherit either mutate or normal chromosomes, and the probability of developing hemophilia is 50%.

Odds of a male son being hemophilia carrier 

In males, the mutated chromosome is enough for the development of hemophilia, meaning that the male cannot be a carrier of hemophilia in this case. 

Odd of offspring developing hemophilia. 

There is a 25% odd that the son will have hemophilia, a 25% chance that the daughter will be a hemophilia carrier, and a 50% probability that the two people will have mutated genes. 

The reason why some offspring developed the disease 

Significantly, for hemophilia development, only the offspring that have mutated  X chromosome will develop the disease.  In the case of a daughter, it will be impossible for them to develop hemophilia, for they receive the gene from the father who is unaffected by hemophilia (R et al., 2018).  In the male case, the sons will be having a 50% chance of receiving their mother’s healthy gene; in this case, she is a carrier. 

Reference

Lockhart, J. (2018). Suspended animation: A transcriptional module triggers embryo formation in suspensor cells. The Plant Cell, 31(1), 5-6. https://doi.org/10.1105/tpc.18.00975

R, V., P, N., & N, S. (2018). Survey on the genetic variation among the students. Insights in Biomedicine, 03(01). https://doi.org/10.21767/2572-5610.10041

Peer 2

Describe the Punnett Square and what it used to predict. What are the limitations of the Punnett Square?

The Punnett Square is a diagram that shows the matting pattern of two individuals with an autosomal dominant gene. (McCance, 2019) The Punnett square was created by Reginald C. Punnett and was used to predict the traits of offspring based on the traits of their parents, this diagram is now the basis of most school teaching of genetics. (Adelman, 2017) The Punnett squares can be used in complicated situations but there are easier genetic squares that can be used when it come to a more complexed situation. (Taylor, 2019).

Scenario: Mom is a carrier for hemophilia but does not have the disease.
Dad does not have hemophilia..

• What is the probability a female offspring developing hemophilia?

There is zero probability of the female offspring developing hemophilia. 

• What is the probability of a female offspring being a carrier for hemophilia?

There is a 25% percent probability that the female offspring will be a carrier of hemophilia

• What is the probability of a male offspring developing hemophilia?

There is a 25% chance that the male offspring will develop hemophilia and a zero percent chance that the male will be a carrier of hemophilia. 

• What is the probability of a male offspring being a carrier developing hemophilia?

There is zero chance that the male will be a carrier of hemophilia. 

• What is the probability of any offspring developing hemophilia?

If there are two children, the probability of any offspring developing hemophilia it would be a 25% chance

• Explain why only some offspring would develop the disease?

The reason why only some offspring would develop hemophilia is due Approximately 30% of cases of hemophilia are caused by a spontaneous mutation of the gene. In some cases, the mother is not a carrier of hemophilia, and the child is affected. This child may be the first in the family to have hemophilia and to carry the defective factor gene. In some cases, the genetic mutation occurs in the mother, and she finds out she is a carrier (through DNA testing) after she has a child with hemophilia. (www.hemophiliafed.org)

Reference:

Adelman, J. (2017, June 08). The Punnett Square: Predicting the traits of offspring based on the traits of their parents. Retrieved December 19, 2020, from https://www.irishtimes.com/news/science/the-punnett-square-predicting-the-traits-of-offspring-based-on-the-traits-of-their-parents-1.3102939

McCance, K.L., Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children. St. Louis, MO: Elsevier

Taylor, Courtney. (2020, August 26). Probability and Punnett Squares in Genetics. Retrieved from https://www.thoughtco.com/probability-and-punnett-squares-genetics-4053752

https://www.hemophiliafed.org/understanding-bleeding-disorders/what-is-hemophilia/hemophilia-a/inheritance-pattern/