X-linked and Autosomal Inheritance Patterns Assignment Requirements
1. Discuss the differences between x-linked and autosomal inheritance patterns, and give an example of each. What causes these differences in transmission?
2. Go to You-tube and find a video on genetic disorders. Tell your classmates about the video. What did you find new or helpful? How does the information support what you have learned in this class? Be sure to include the website for the you-tube video you watched in your posting
Differences between X-Linked and Autosomal Inheritance Patterns
The inheritance of genetic conditions follows predictable patterns that can be used to predetermine the possibility of parents passing a particular genetic makeup, which determines the phenotypic characteristics of the child. The autosomal and X-linked inheritance patterns describe the transmission of genetic conditions in families and the recurrence risk depending on whether the pattern is recessive or dominant (Finsterer, et al., 2012). The autosomal inheritance patterns occur either as dominant or recessive. In autosomal dominant inheritance, only a single copy of an allele is needed to make an individual susceptible to the development of the phenotypic characteristics. As such, there is a 50 percent probability for the child to inherit the allele for the particular genetic condition. The phenotype is observed in heterozygous or in homozygous. For example, Huntington disease and myotonic muscular dystrophy reveal autosomal dominant inheritance. Moreover, autosomal recessive inheritance is observed when a person possesses two copies of the genetic condition otherwise the person becomes a carrier. Examples of this form of inheritance include cystic fibrosis and sickle cell anaemia. While this is the case, the X-linked inheritance pattern requires the X chromosome to have only one copy of the disease allele for the child to reveal susceptibility to an X-linked disease. Male and females are affected but males, who carry only one copy of the genes found on the X-chromosome are more severely affected. When the female parent is affected, there is a 50 percent of the child to inherit the disorder while when the male is affected all the daughters are affected but the sons are not affected. The X-linked disorders include the fragile X syndrome and the oral-facial-digital syndrome type I (National Insitutes of Health, 2016).
Chapman (2013) discusses the patterns of inheritance through specific examples of
the genetic disorders. In the video, the author asserts that changes in the
genome, which occur in the sex cell can be passed to offspring as genetic
conditions. The change is either in the number of chromosomes or as a result of
mutation of the chromosome itself. He discusses sickle cell anaemia, Tay-Sachs,
Down syndrome, Klinefelter’s syndrome, X-linked color blindness, and Huntington’s
disorder. The author outlines that the Klinefelter’s syndrome and Down syndrome
occur due to the change in chromosome number while the rest are caused by the
change in the chromosome structure. Chapman supports the inheritance patterns
as studied in class such as the causes of the diseases and the probability of
the children to inherit the conditions. I found the presentation using the
specific examples useful in enhancing understanding of the differences between autosomal
and X-linked inheritance patterns.
Chapman, J. (2013, December 16). Human Genetic Diseases to Know. Retrieved from YouTube
Finsterer, J., Löscher, W., Quasthoff, S., Wanschitz, J., Auer-Grumbach, M., & Stevanin, G. (2012). Hereditary spastic paraplegias with autosomal dominant, recessive, X-linked, or maternal trait of inheritance. Journal of the Neurological Sciences 318 (1- 1-2), 1-18.
National Insitutes of Health. (2016, January 18). What are the different ways in which a genetic condition can be inherited? Retrieved from U.S. National Library of Medicine – National Insitutes of Health: http://ghr.nlm.nih.gov/handbook/inheritance/inheritancepatterns