While many parts of the human body can be highly complicated, a very simple little portion of the body can control all aspects of the development, growth, and life of a human being. This relatively simple structure is called DNA.
The cells of the human body also contain several important structures. Some of common components are:
Cell wall: All the cell components are enclosed by this thin membrane.
Mitochondria A portion of the cell containing enzymes important for energy creation within the cell. This structure also contains its own DNA elements.
Vacuoles: A single membrane surrounding waste products of the cell.
Nucleus: The largest component in the cell. It contains all of the nuclear DNA or 23 chromosome pairs that determine the genetic identity of an individual. There are a total of 46 chromosomes in the nucleus, 44 autosomes and 2 sex chromosomes. The chromosomes are important because they are comprised of DNA.
All cells in the human body except the red blood cells
contain DNA. The DNA is located in the nucleus at the center of the cell.
DNA contains all the information necessary for the development of all the
functions of your body. That’s a considerable amount of information! In
fact, a typical human cell contains a meter of DNA tightly wrapped in
configurations we call chromosomes. We each have 46 total chromosomes, which
are grouped into 23 pairs, each pair consisting of one chromosome from our
mother and one from our father.
A chromosome is formed from a single DNA molecule that contains many genes. The genes are the informational units of DNA. The human genome is estimated to contain 30,000 to 40,000 genes. The human genome consists of only 2% of genes; the remainder consists of uncoded regions, with varying functions from giving structure to the chromosome, to having no known purpose. These segments of “junk DNA” as they are sometimes called, are useful for genealogical purposes.
The most useful chromosome in genealogy is the Y chromosome. The 23rd chromosome pair is two X chromosomes in females, but in the male there is an X and a Y. The Y chromosome is what determines the male gender. The Y chromosome has the unique distinction of being passed practically unchanged from one generation to the next. This means that a man passes on the same Y chromosome to all his sons. Similarly, he will have the same Y chromosome as his father, grandfather and so on. This gives the Y chromosome the valuable genealogical property of following the surname.