April 7th, 2013
Humans have diverged genetically since we emerged from Africa about 100,000 years ago (Stearns & Koella, 2007). The impressive diversity of humans in the planet establishes that each human is unique in their traits and characteristics. Those traits describe our genotype, the complete inherited makeup of an organism (Mossler, 2011). The genes of both parents play a crucial role in the genotypes and phenotypes of a human being; this predisposition will also be marked by environmental factors that will determined the condition of a child. In the complex elaboration of humans, even genetic can develop abnormalities that will create chromosomal disorders. “Down syndrome is the most common chromosomal abnormality reaching viability” (Ramalho, Brandao, Matias, & Montenegro, 2011). In essence, we will review how genetic background plays a powerful role in human outcomes, both in normal or abnormal conditions.
Genetic code of humans is the result of the combination of a mother’s ovum and father’s sperm into a unique cell which will turn into trilllions of them (Mossler, 2011). Each cell is a chromosome containing genetic information. Cells contain a nucleus with 23 pairs of chromosomes composed of DNA, and genes are parts of DNA containing hereditary data (Mossler, 2011). Genes in the 46 chromosomes inside our cells mark the development and function of every system in our body (Gupka, Kabra, & Deka, 2010). Each child will have half his or her genes from each parent. Genotypes such as height, eye color, shape of the earlobe, and hairline will be inheritated from the parents, once genotypes such as intelligence and motor skills interact with the environment observable behaviors or phenotypes will be produced (Mossler, 2011). For instance, the phenotype for skin color will be determined by a number of genes, “traits and diseases are determined...