Download Introduction to Genetics (Genetics)

Introduction to Genetics (Genetics)
Genetics, study of the function and behavior of genes. Genes are bits of biochemical instructions found
inside the cells of every organism from bacteria to humans. Offspring receive a mixture of genetic
information from both parents. This process contributes to the great variation of traits that we see in
nature, such as the color of a flower’s petals, the markings on a butterfly’s wings, or such human
behavioral traits as personality or musical talent. Geneticists seek to understand how the information
encoded in genes is used and controlled by cells and how it is transmitted from one generation to the next.
Geneticists also study how tiny variations in genes can disrupt an organism’s development or cause
disease. Increasingly, modern genetics involves genetic engineering, a technique used by scientists to
manipulate genes. Genetic engineering has produced many advances in medicine and industry, but the
potential for abuse of this technique has also presented society with many ethical and legal controversies.
Genetic information is encoded and transmitted from generation to generation in deoxyribonucleic acid
(DNA). DNA is a coiled molecule organized into structures called chromosomes within cells. Segments
along the length of a DNA molecule form genes. Genes direct the synthesis of proteins, the molecular
laborers that carry out all life-supporting activities in the cell. Although all humans share the same set of
genes, individuals can inherit different forms of a given gene, making each person genetically unique.
Since the earliest days of plant and animal domestication, around 10,000 years ago, humans have
understood that characteristic traits of parents could be transmitted to their offspring. The first to
speculate about how this process worked were Greek scholars around the 4th century bc, who promoted
theories based on conjecture or superstition. Some of these theories remained in favor for several
centuries. The scientific study of genetics did not begin until the late 19th century. In experiments with
garden peas, Austrian monk Gregor Mendel described the patterns of inheritance, observing that traits
were inherited as separate units. These units are now known as genes. Mendel’s work formed the
foundation for later scientific achievements that heralded the era of modern genetics.