Definition
Genetics is the study of heredity, the process in which a parent passes certain genes onto their children. A person's appearance -- height, hair color, skin color, and eye color -- are determined by genes. Other characteristics, such as mental abilities, natural talents, and your susceptibility to develop certain diseases, are also affected by heredity.
An abnormal trait (anomaly) passed down through families (inherited) may:
- Have no effect on your health or well being -- for example, it may just involve a white patch of hair or an extended ear lobe
- Be of minor consequence -- for example, color blindness
- Have dramatic effect on ypur quality or length of life
For most genetic disorders, genetic counseling is advised. Many people may also want to seek prenatal diagnosis.
The terms anomaly, abnormality, disorder, defect, disease, and syndrome are not used consistently, and do not have precise definitions.
Alternative Names
Homozygous; Inheritance; Heterozygous; Inheritance patterns; Heredity and disease; Heritable; Genetic markers
Information
Human beings have cells with 46 chromosomes -- 2 sex chromosomes and 22 pairs of non-sex (autosomal) chromosomes. Males are "46, XY" and females are "46, XX". The chromosomes are made up of extremely long DNA molecules in combination with proteins.
Genes are defined by intervals along one of the DNA molecules. The location of the gene is called the locus. Most genes carry information which is necessary to make a protein.
The pairs of autosomal chromosomes (one from the mother and one from the father) carry basically the same information. That is, each has the same genes, but there may be slight variations of these genes. These slight differences occur in less than 1% of the DNA sequence and produce variants of a particular gene that are called alleles.
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