Question

 

Overview Most disorders or diseases are caused by a combination of environmental and genetic factors. However, some are caused solely by genetics. We are going to examine the latter in this discussion. You will be given the choice of a genetic disorder to research and write about, and then you will draw some conclusions based on this information. You should spend approximately 3 hours on this assignment.

Instructions Choose one genetic disorder from the following list: Sickle cell anemia Cystic fibrosis Duchenne muscular dystrophy Achondroplasia

Conduct some research on the disorder you chose (remember to write down your sources). Start your discussion post with a description of the genetic disorder. Focus on the inheritance pattern of the disorder (autosomal dominant, X-linked, etc.) and the genotype and phenotype of a person with the disorder.

In your initial post, delve more deeply into the inheritance of the disorder by answering the following questions: What has changed in that gene to allow it to cause a genetic disorder? Be specific and explain how this differs from the gene’s normal function.

Is it possible for parents to not have the disorder, but pass it on to their children? What kind of dominance pattern does it show?

What problem(s) is/are caused to a person who inherits this gene? Is this gene typically inherited from the mother or the father? Finally, describe an experiment that you could use to determine if a new drug is effective at treating the disorder. Be sure to mention the independent, dependent and control variables

Finally, consider how you could use the scientific method to draw conclusions about this disorder or to treat this disorder.

 

Answer 1

SICKLE CELL ANEMIA

Sickle cell anemia is one of the inherited RBCs disorder in which RBCs are not capable enough to carry oxygen in blood throughout the body because of disordered structure. RBCs attain a sickle like shape and get stuck in blood vessel. Thereby slowing down the blood flow. It occurs when people inherit 2 abnormal copy of beta globin gene one from each parent

GENETICS

• Sickle cell anemia is an autosomal recessive disorder. Both the copies of beta gene should be mutated to cause the disease.
• Both parents should either be carrier or affected to pass the disease to there offspring. When both the parents are carrier then there are 25% chances for the child to have sickle cell anemia.
• People who have one defective gene they do not get disease but they may pass on the disease to the offspring. The disease is caused due to mutation in the beta globin gene.
• It is termed as genetic disorder as disease arises due to mutation at the gene level thereby resulting in altered protein formation. The mutation is single nucleotide mutation. Change in one nucleotide from A to T causes the codon change from GAG to GTG. This change results in change of amino acid from glutamic acid to valine.
• Valine being a non polar amino acid affect the structure of hemoglobin which serve as oxygen carrier.
• Being a benign mutation there is no alteration in structure at normal oxygen level
• The deoxy form of hemoglobin exposes E and F helix because of which it results in fibrous precipitate and polymerization. Thus, polymerization forms distort shape of RBCs thereby making fragile and break by getting stuck in capillaries.
• In case of healthy people the structure of oxy as well as deoxy form is biconcave or doughnut like shape. There are no structural alteration seen in hemoglobin because of which normal oxygen transport can take place throughout the body. As RBCs are not susceptible for breaking and getting stuck in capillaries.
• The carrier who do not have disorder but can pass on the disease to their child. Inheritance pattern for carrier and affected individual are shown in figure.
• The genotypic make up for healthy person- RR, affected person- rr, carrier person- Rr. Phenotype is the sickle shape of RBCs

EXPERIMENTAL DESIGN FOR TREATMENT

• Western blot analysis of the hemoglobin protein before and after the treatment of the drug.
• The deoxy and oxy state of hemoglobin protein is treated withe the drug at various concentration and time duration
• The normal hemoglobin, and  defective hemoglobin without the treatment as controlled variable
• The concentration of the drug as well as time duration were the independent variable as there effect was measure on hemoglobin
• The hemoglobin which was treated with drug was the dependent variable.
• After the treatment the hemoglobin structure was studied with the help of western blot analysis and compared to the control variable.
• The structure alteration can also be studied with the help of microarray technology in which the fluorescent dye show difference binding pattern to the normal defective hemoglobin