The Punnett square is a descriptive way of predicting the likelihood of certain traits being inherited (O’Neill, 2012). The Punnett square acts of a graph that will show the probability of each of the inheritable genotypes that can happen, based on the genotypes of the parents that are used. Although this tool is helpful, it is based on prediction. That means that it is based on chances, and making it not always accurate, which causes there to be limitations with the Punnett Square.
Mom is a carrier for hemophilia but does not have the disease.
Dad does not have hemophilia
Using the Punnett Square, answer the following questions:
- What is the probability of a female offspring developing hemophilia?
- There is not a chance that the female offspring will develop hemophilia.
- What is the probability of a female offspring being a carrier for hemophilia?
- There is a 50% chance that the female offspring will be a carrier for hemophilia.
- What is the probability of a male offspring developing hemophilia?
- There is a 50% chance that the male offspring will develop hemophilia.
- What is the probability of a male offspring being a carrier developing hemophilia?
- There is not a chance that the male offspring will be a carrier developing hemophilia.
- What is the probability of any offspring developing hemophilia?
- The probability of any offspring developing hemophilia is 25%, where 50% of the males are at risk.
- Explain why only some offspring would develop the disease?
- The father does not carry the genotype for hemophilia, whereas the mother is just a carrier. This would leave no female risk for developing hemophilia, and only a 25% chance of them being a carrier. There is a 50% chance that the male would develop hemophilia, but no chance that they would be a carrier.
O’Neill, D. (2012). Probability of Inheritance. Basic principles of genetics: Probability of inheritance. Retrieved from https://www2.palomar.edu/anthro/mendel/mendel_2.htm.
Understanding the human body or any other living organism is quite complex. Such a process takes into account a proper analytical process which would involve analyzing everything up to the tiniest detail. One of the ways through which such a process is made possible is by understanding genetics. Genetics is associated with heredity, and it is linked to the composition of a person or organism, the way they look, and even some of the behavior. Genetics helps in explaining various things that may be difficult to understand in just a simple analysis. However, for such an analysis to happen, there are specific tools that are commonly used. One of such tools is the Punnet Square which forms the discussion below.
Describe the Punnet Square
The Punnet Square is a somewhat famous genetic analysis tool that is always used by geneticists. From the name itself, it consists of a diagram that is square-like. The square-like diagram is considered to be essential, especially in the prediction of the various genotypes of an offspring. The prediction is always made from a cross experiment or even breeding. The Punnet Square was first formed in the year 1905 by Reginald C. Punnett (Hurst, 2019). The Punnet Square is rather simple to use and to create, but before the creation, there has to be proper information about the parents.
The genotypes of the parents are needed, and finding them is essential. After the genotypes have been gotten, the gametes of the parents are placed in some kind of tabular form. There are always other small boxes found in Punnett Square, and each of those boxes happens to indicate some kind of fertilization event (Lombardo, 2018). The Punnet Square is also composed of various assumptions. An example of an assumption is that the various traits tend to be dispersed independently.
What the Punnet Square is Used to Predict
The Punnet Square is always used in the prediction of the probability of an offspring getting some specific traits from a parent. It can therefore be said that the Punnett Square is useful in predicting probability. The Punnett Square works to provide predictive values of some kind of outcome based on a genetic comparison between two parents (Hartsfield et al., 2017). The Punnet Square tends to show the chance of an event happening.
The Punnett Square provides ways through which probability can be calculated. The calculations are based on the use of various rules that exist in Punnett Square. Two such rules include the sum and the product rule. The mentioned rules are essential, and they can be used differently to predict a certain value. The rules are essential in the prediction of probability.
What are the Limitations of the Punnet Square?
The Punnet Square has always proved to be effective over the years, but it still has its own set of limitations. A good example of the limitations is that the Punnet Square can only be useful when conducting a genetic evaluation of simple genetic comparisons or situations (Addolorato, 2018). The Punnet Square can only be used to predict the genetic composition of an offspring from two parents. There is no other additional comparison it can be used for. Its simplicity makes it impossible to be used when making complex genetic comparisons.
Therefore, it is impossible to use the Punnet Square even when trying to estimate the distribution of either phenotypes or even genotypes. Another major limitation that the Punnet Square has is that it is impossible to use it to come up with accurate predictions of the distribution of the phenotype of an offspring (Cunningham & Thomas, 2020). The prediction is not possible when three or more multiple genes are useful in the determination of a single trait. It is even impossible to grade the effect linked to one gene.
Using the Punnett Square, Answer the Following Questions:
What is the Probability of a Female Offspring Developing Hemophilia?
After the construction of the Punnet Square, it is possible to predict that the probability of a female offspring developing hemophilia is twenty-five percent.
What is the Probability of a Female Offspring Being a Carrier for Hemophilia?
The calculations from the Punnett Square indicate that the probability of a female offspring developing hemophilia is twenty-five percent.
What is the Probability of a Male Offspring Developing Hemophilia?
The calculations from the Punnet Square show that the probability of a male offspring developing hemophilia stands at twenty-five percent.
What is the Probability of a Male Offspring Being a Carrier for Hemophilia?
The calculations from the Punnett Square do indicate that the probability of a male offspring being a carrier for hemophilia is twenty-five percent.
What is the Probability of Any Offspring Developing Hemophilia?
The calculations from the Punnet Square do indicate that the probability stands at fifty percent.
Explain Why Only Some Offspring Would Develop the Disease?
The mom is the only carrier for hemophilia which means that some of the offspring would inherit the X chromosome having hemophilia while some would not.
To summarize all that has been discussed, the Punnet Square is a useful tool and will continue to be used by many. It has its weaknesses and limitations, but it also has its advantages and usefulness. The Punnet Square is always simple to use, and it is not that complex. A good example has been discussed above from the situation of hemophilia.
Addolorato, S. (2018). Product or service tangible and intangible variables: the creation of the itness application “punnett square” (faps). Sport TK: Revista Euroamericana de Ciencias Del Deporte, 7(2), 9–16.
Cunningham, C., & Thomas, M. (2020). Methods to Determine the Phenotypic Ratio of a Hybrid Cross (p. 2020).
Hartsfield, J. K., Jacob, G. J., & Morford, L. A. (2017). Heredity, genetics and orthodontics: How much has this research really helped? Seminars in Orthodontics, 23(4), 336–347.
Hurst, L. D. (2019). A century of bias in genetics and evolution. Heredity, 123(1), 33–43.
Lombardo, P. A. (2018). The power of heredity and the relevance of eugenic history. Genetics in Medicine, 20(11), 1305–1311.