Each chromosome consists of a double strand of DNA attached to proteins called histones.
The genes, which contain the genetic material that controls the inheritance of traits, are arranged in a linear pattern along the length of each DNA strand.
Each species has a characteristic number of chromosomes in each somatic cell. In humans, there are forty-six chromosomes, including twenty-two homologous pairs of autosomes and one pair of sex chromosomes.
One member of each pair is derived from each parent.
It is useful in evaluating congenital anomalies, mental retardation, and delayed puberty as well as in the prenatal diagnosis of serious congenital diseases; such as, Klinefelter syndrome and Down syndrome and other suspected genetic disorders.
Used as a diagnostic for particular diseases; for example, types of leukemia.
It is indicative of gene activity; specifically, DNA and RNA synthesis at that site.
Such bands appear at certain chromosomal locations within a given tissue at specific developmental states in insects and are significant in the study of the mode of genetic transmission.