Mendel's Principles Of Inheritance: Case Study

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In the mid of 1860s, an Austrian monk named Gregor Mendel began to cross-bred peas plant and observed how the traits of the peas plants interacts with each other as they are passed down to their offspring. Based on his research data and recording, Mendel proposed the Principles of Inheritance (Numbers, 2013). The Principles of Inheritance contained three separate laws, each is vital in understand heredity on its own.
The first law is the Law of Segregation, which states that within every trait in an organism contains two variations of the trait known as allele (Miko, 2008). During meiosis, the alleles separate from each other and placed into individual gamete each containing a different allele. When two gametes from the parent organisms meet
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However, there are forms of trait inheritance that exists outside of the Mendelian principles, such as sex-linked genes. Genes that are sex-linked is located on the sex chromosomes. In mammal, there are two sex chromosomes, X and Y. Female have two X chromosomes, while male have one X and one Y chromosome (Kirkpatrick and Hall, 2004). As a result, male have a higher chance of inheriting a sex-linked genetic disorder since it only requires one copy of the X chromosome for the disorder to be in effect. Furthermore, because males only have one X chromosome, they cannot be a carrier for a sex-linked disorder. On the other hand, females have two X chromosomes, therefore, two copies of the X chromosomes with the genetic defect is required in order for the disorder to be present, additionally, it is not uncommon for a female to be a carrier of certain sex-linked disorders. Although not as prevalent, Y-linked genetic disorders exists and it is commonly known as holandric inheritance. Since the size of a Y chromosome is much smaller than that of an X chromosome, it does not contain anywhere near as much genetic information. In other words, there is not many genetic disorder that is responsible by the holandric inheritance in comparison to X-linked inheritance. Y-linked genetic disorders is limited to male since there are no Y chromosome in a female (Wang et al., 2012). Sex-linked disorders can be …show more content…
Furthermore, the life cycle of an average fruit flies’ life cycle from eggs to adults is approximately 13 days with a range of 10 to 20 days. They are ready to mate within 10 hours after they have emerged from their pupa case. On average the flies lay about 50 to 100 eggs per days, all of this combine with the fact that they are relatively inexpensive to maintain and care for (Marshall, 2016). In fruit flies, just like every other organism, there exists different alleles for each characteristic. This variation in appearance or phenotype is responsible by the coding of protein within each organism, otherwise known as the central dogma of molecular biology. The central dogma can be briefly summarized as sequence of DNA being transcribe into mRNA, which then get translate into amino acids or proteins. DNA sequence varied from one another and the final gene product or protein also varied from one another (Crick, 1970). Since proteins is what responsible for the phenotype in organism, the variation in proteins also means that there are dissimilarities between the phenotype of

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