Inheritance Patterns

Dr V L Ramprasad, COO, MedGenome, gives an insight on ways to improve global health by decoding the information contained in an individual’s genome.

- V L Ramprasad

A FAMILY’S health history if recorded correctly through the years helps to understand how traits are passed on to their future generations. This set the pace for understanding the way familial characteristics are passed on from one generation to another is based on the patterns of inheritance discovered by an Austrian scientist and monk, Gregor Mendel. He is known as the father of modern genetics researched and discovered the essential patterns of inheritance during conducting experiments in the garden of the monastery he lived in. Mendel's studies of inheritance patterns in pea plants are a solid foundation for our current understanding of single-gene diseases in humans. Inheritance patterns describe how a disease is transmitted in families.

Through his research, Mendel inferred that human genes are present in pairs, one of each pair inherited from each parent. Some genes undergo changes which don’t impact their functioning but the changes known as mutations do influence the functioning of the genes and may lead to disease. Such diseases are also called as Mendelian or monogenic diseases and they sometimes run in families. In the case of some families, members whose genes may experience a similar mutation don’t necessarily have to experience the same symptoms (recessive). However, in the case of some other families, members whose genes experience dissimilar mutations may inherit the same traits/disease (dominant). Pedigree analyses of large families with many affected individuals can be used to determine whether a disease-associated gene is located on an autosome or on a sex chromosome, and whether the related disease phenotype is dominant or recessive.

Different patterns of inheritance