Question

Define Human Genetics. What arethe major branches and fields of human genetics?

Answer 1

Major Branches and Fields of Human Genetics:

• According to some there are two major branches of human genetics, one is physiological genetics and the other is population genetics.
• To others the two main branches are formal genetics and population genetics.
• Some like to make another main branch called medical genetics, which is rapidly developing during recent times because of its immense applied value.
• There are several other fields of human genetics.
• It is difficult to put clear cut lines separating one field from the other, as the borders are not distinct and there are overlappings.
• Neel and Schull (1954) have defined physiological genetics as "that branch of genetics which is concerned with working out the intermediary steps whereby the presence of a given gene, as a member of a particular genotype and in a particular environment, is responsible for the appearance of a given trait.
• According to Vogel and Motulsky "formal genetics studies segregation of Mendelian genes and investigates more complex types of inheritance".
• Thus, the main thrust of physiological genetics and formal genetics is more or less the same.

Population genetics:

• This is concerned with the nature and extent of distribution of different genes in various human population groups because of the effects of mutation, selection, genetic drift and gene flow.
• The genetic structure of a population is determined by these factors
• . There are two approaches to study human population genetics.
• One, to describe the populations in terms of their composition and, two, to account for the causes of genetic variabilities in the pouplations.

The study of epidemiology applying biometric techniques is also included in population genetics.

Medical genetics (Clinical genetics):

• This concerns with diagnosis and prognosis of various genetic diseases.
• It is gaining importance because it deals with treatment of such diseases as well.
• Moreover, genetic counselling forms an important field of medical genetics.

Human cytogenetics

• Human chromosome i:n relation to health and disease are investigated in the field called human cytogenetics.

Immunogenetics:

• On the other hand, immunogenetics deals with different blood groups and tissue antigens.

Pharmacogenetics:

• It concerns itself mainly with reaction between genetic factors and drugs.

Developmental genetics:

• In recent times attempts have been made to study normal and abnormal development because of genetic background and mechanism in the field of developmental genetics.

Reproductive genetics:

• This concerns details of gamete and formation of embryo.

Behavioural genetics:

• The hereditary factors related to behaviour in health and disease are of the concern of behavioural genetics.
• These fields in general are covered by medical or clinical genetics.

Somatic cell genetics:

• The transmission of genes at the level of cells is studied in that field of human genetics is called somatic cell genetics.

Biochemical genetics

• Human biochemical genetics concerns with the study of biochemistry of proteins, enzymes and nucleic acids, and also inborn errors of metabolism. Molecular genetics deals with the molecular structure of genetic materials and also its functional significance.

Human Genetics:

• The human genetics is a branch of biology which deals with the inheritanc of traits from one genration (parents) to next generation (children).