Heredity and Its Influence on One's Looks

"Did she inherit her mother's looks"? "What made her act like that"? Genetics may not provide us with ready answers to many of our "nature" or "nature" questions. But it does offer a means for identifying problems of heredity.

The small particles which contain the genes responsible for hereditary traits are called chromosomes. Chromosomes are found in pairs in all he cells of the body. The human cell has forty six chromosomes arranged in twenty three pairs; one member of each pair deriving from the mother and the other from the father. The genes, the actual trait carriers, are found in innumerable numbers in each chromosome. In recent years, the symbols 'DNA' and 'RNA' have almost become household terms, oversimplified as the substances of life and even developed in the laboratory.

What are these DNA and RNA? DNA stands for deoxyribonucleic acid, a substance that is primarily responsible for genetic inheritance and RNA, ribonucleic acid. These complex chemical chains work together. This 'chemical package' determines physical characteristics, such as color of the eyes, characteristics of brain, baldness and the many other factors we inherit.

The genetic code has been called a 'racial memory' since the DNA molecules found in the fertilized ovum remembers what the parents were like and pass the message along. RNA acts as an assistant to DNA. DNA remains the cell's nucleus directing the cell's activities by manufacturing RNA, which moves out to control cellular functions.

Studies support the theory that when nerve cells are stimulated, RNA molecules inside them give orders to manufacture new proteins, which may in some unknown way record what has been perceived and so relate to the process of memory. The understanding is that RNA can be altered in such a way as to form the biochemical storage unit for information about how proteins in nerve tissues are produced. These proteins, in turn determine how the neural elements respond to new stimulation.

A fertilized zygote brings together various combinations of chromosomes and thus different genes are given to each child of the same parents. This is why each child is somewhat more similar to his blood relatives than to outsiders. This is also the reason why there may be wide variations within the same family. Only identical twins will have identical chromosomes and genes. They are formed by the division of a single zygote. Fraternal twins are developed from two separate zygotes.

They may resemble each other somewhat but often are quite different: One may be stocky and his twin thin and tall; one may be quiet and thoughtful, yet aggressive and his brother may be outgoing but lacking aggressiveness. It is as though some genetic engineering has been put into play.