1. The main aim of the Human Genome Project was to determine the DNA Sequence of every human gene.
2. Variation in skin colour is an example of polygenic inheritance
This Human Karyotype is unusual because it has an extra chromosome at chromosome 21.
Klinefelters syndrome is shown in the second figure
Explanation:
1. The Human Genome Project's main goal was to sequence all the 30,000 genes and 3 million base pairs in their makeup for the early detection of diseases, gene therapy and molecular level studies.
2. Human skin colour is determined by the pigment melanin. The Dominant allele is responsible for dark colours as it produces more melanin. The melanocortin 1 receptor (MC1R) gene and Tyrosinase enzyme codes for the human skin colour. Polygenic inheritance are the traits which are controlled by one or more genes.
<u>figures:</u>
<u>The extra chro</u>mosome at the 21st chromosome pairs is called trisomy 21 or Down's Syndrome. It is due to the abnormal cell division/meiosis resulting in an extra X chromosome. This leads to thechanges the in physical development of the individual.
Klinefelter's Syndrome: There are 47 chromosomes and 2 or more X chromosomes in this syndrome of males. The resulting male suffering from Klinefelter would be sterile and have poorly developed testicles.
