PSY104: Child and Adolescent Development
Instructor Laura Inman
November 19, 2012
The Role of Genetics on Development
Our bodies are governed by individual instructors, or genes, which decide how we are to develop and function. Genes are responsible for our physical and medical characteristics that include hair color, blood type, and an individual’s susceptibility to disease. Chromosomes are the structures that are made up of thousands of genes. Chromosomal disorders are caused by an abnormality of chromosome number or structure. According to the Encyclopedia Britannica (2012) chromosomal disorders are defined as any syndrome characterized by malformations or malfunctions in any system of the body which are caused by an abnormal chromosome number or structure. The normal and abnormal number and structures of genes and chromosomes are the foundation of genetics, or the biology of inheritance. An individual’s genetic sex is determined at the time of fertilization of the ovum by the sperm. Chromosomal abnormalities usually occur when there is an error in cell division. Twenty-two of the twenty-three pairs of chromosomes determine physical development with an individual independent of the person’s sex. The final pair, twenty-third pair, consists of two sex chromosomes, which determine whether the individual is to be a female or male. Females have two X chromosomes (XX) while males have an X and a Y chromosome (XY). Female chromosomes are described as 46,XX; male chromosomes as 46,XY. Two of the most common chromosomal disorders, Klinefelter’s syndrome and Turner syndrome, show discrepancies with cytological identification of the sex chromosomes of developmental sex deviants. Individuals with Klinefelter’s syndrome usually have an XXY chromosomal sex type. These individuals are usually male in most phenotypic respects, except that...