Genetics affects our lives in many ways. It is the study of heredity, genes, an inherited trait, patterns in genetic information mutations and genetic variation in living organisms. Chromosomes are the genetic material of an organism, which is composed of proteins and DNA molecules. There are 23 pairs of chromosomes, which are inherited from parents. The 23rd pair of a chromosome is the sex chromosome which decides the sex of an individual. Abnormalities in genes can give rise to several disorders which have a powerful effect on both individuals and their families. Similar to other chronic and infectious diseases, these genetically inherited diseases may also lack accurate and effective treatment and in several cases have no cure.
Also Read: Chromosomal Theory of Inheritance
Classification Of Diseases On Genetic Bases
As per medical records, every year more than 2 million children are born with a series of Genetic Disorders. Established on a genetic basis, these diseases are classified into:
Caused by the combined action of more than one gene. It is also called as the multifactorial inheritance. Examples of polygenic disorders are Cancers, Cardiovascular diseases, Diabetes mellitus, Hypertension, and other non-communicable diseases.
Caused by a mutation in a single gene. It is also called Mendelian disorders. Examples of monogenic disorders are Colour blindness, Neurofibromatosis, Phenylketonuria, Rickets, etc.
Caused either by a defect in the chromosomes or in the arrangement of the genetic material on the chromosome. Examples of chromosomal aberrations are Down syndrome, Klinefelter’s syndrome, Leber’s hereditary optic neuropathy, Structural abnormalities, Turner’s syndrome, etc.
Also Read: Chromosomal Abnormalities
Q.1. Who is the father of modern human genetics?
A.1. James Neel
Q.2. What do you understand by incomplete dominance?
A.2. It is a kind of intermediate inheritance wherein one allele for a particular characteristic is not fully expressed on its paired allele which causes a third phenotype resulting in the expressed physical trait to be a combination of phenotypes of both the alleles.
Q.3. Can you give one example of co-dominance?
A.3. Expression of both A allele and B allele in a person with blood group type AB
This was a brief introduction to the impact of Genetics on human lives. Stay tuned with BYJU’S to know more biological concepts in detail such as inherited diseases, infectious and other non – communicable diseases.