Biology - Human Genetics - Coursework Example

Show the genotypes of the parents, the genotypes of the gametes and all the possible genotypes of their offspring. Label the phenotype of each of these offspring. Fertilisation. Paternal gametes Maternal gametes HbA HbS HbA HbA HbA HbS HbA HbS HbA HbS HbS HbS i.The first child born to the couple in (a) has blood that contains haemoglobin S only. Referring to your answer to part (a), what is the probability of this outcome? The probability of the outcome is given by the number of ways to get the disease divided by the total number of possible outcomes= 1/4. ii. What is the probability that a future child born to this couple will have the sickle cell trait?

Explain your reasoning. The probability that a future child born to this couple will have sickle cell trait is 3/4.This is because the parents are heterozygous only one child will not have a sickle cell trait as stated by Dhar (1997, p. 180). b. Studies on the gene for haemoglobin show that just a single base change (a mutation) is at the root of sickle cell disease. A change in one codon in the DNA template strand, from CTC to CAC, results in the production of haemoglobin S rather than haemoglobin A.

What complementary change would occur in the mRNA codon, and what change would this cause in the amino acid sequence of the haemoglobin? In the mRNA CTC will change to AUA. This will change the type of amino acid available. c. Molecules of haemoglobin S behave differently from those of haemoglobin A. Using information from the video sequences describe, in your own words, these differences and the consequent effects on the structure of the red blood cells in the body’s capillaries. (No more than 100 words.) (You practised answering questions based on a video sequence in Activities 13.1 and 17.1 in the Study Guide.) Sickle cells are in a sickle form and lack the ability to carry oxygen.

Normal red blood cells are like doughnuts and carries oxygen. Amino acids sequence of the sickle cell is less by one in number. Sickle cells have valine instead of glutamine acid. When oxygen lacks in the cell, the level blood decreases, the haemoglobin molecules come out of solution, stick together and for chains that create red blood cell to become sickle cell. The blood in the capillaries become deoxygenated hence dark in colour. 2. Article 1‘Dark matter of the genome’ reports on recent research findings showing that the parts of the DNA that do not code for proteins may still have an important role in bodily functioning.

You have learned in the module that only a small proportion of the human genome is composed of genes. a. Using your understanding of the module materials, describe in your own words how the DNA within genes is deciphered. Explain how this DNA can ultimately affect bodily functioning, through translation into amino acids and subsequently into proteins. Use the words base’ and ‘codon’ in your answer. (About 150 words). Deciphering is done through the technique calledPCR, or polymearase chain reaction.

DNA is deciphered through two techniques: PCR and polymerase. PCR call for heat, a patented enzyme and two primers, 16-20 bases DNA. There are various steps involved. Mix the primers with the DNA sample; add free nucleotides, and hot enzyme. Heat the mixture to boiling. The DNA will unzip into its two separate strands.The primers stick on before the two strands as it cools