Introduction
Social behavior is a human characteristic that gets influenced by a number of factors. These factors can be broadly classified into two categories; firstly, genetic factors and secondly, non-genetic factors. Genetic factors include the genes, which are chemical constituents of the human body and are inherited by the parents and non-genetic factors include the environmental influences on the social behavior of an individual. Researchers have proved that genes directly do not govern behavior or personality traits, but genes basically influence these traits. Hundreds of genes act together to influence a single personality trait. So, it is impossible to map a single gene responsible for a particular behavioral pattern in an individual.Therefore, by genetic mapping, the behavior pattern of an individual cannot be studied. At this point, the role of environmental factors and nutrition can be held responsible for influencing the behavior pattern of an individual.
What Is The Molecular Basis of Inheritance?
The molecular basis of inheritance comprises heredity, genes, and their variations. It explains the role of genetic materials like DNA in living beings. For a better understanding of medical genetics, conceptual knowledge about the molecular basis of inheritance is fundamental; Friedrich Meischer, in the year 1869, discovered DNA and named it nuclein. Later, in 1953 double helix structure of DNA was proposed by James Watson and Francis Crick. The basis of inheritance revolves around the following:
-
Chromosomes.
-
DNA (deoxyribonucleic acid).
-
Genes.
Inside the nucleus of every cell, chromosomes are present, which are made up of DNA, and DNA organizes itself to form genes. Each cell has 23 pairs of chromosomes which mean 46 chromosomes. In certain genetic disorders, the number of chromosomes varies. We inherit one set of chromosomes from each parent, representing 23 chromosomes from the mother and 23 from the father.
What Is Meant by Inheritance?
A child inherits genes from both father and mother both. These genes code for traits (like hair color, height, etc.). Genes that code for traits from the parents are of two types, the first dominant and the other recessive. In the Indian subcontinent, black hair color is the dominant trait. So, for example, a gene for the father with black hair could be coded as BB (dominant) or BB (codes for black color), and genes for the mother with brown hair will be coded as BB (recessive). Now, the following could be the probable hair color of the child depending on the combination of the gene the child inherits.
-
BB- (black) 25 % of the children.
-
BB- (black) 50 % of the children.
-
BB- (brown) 25 % of the children.
So, the ratio between black and brown hair color is 3:1; hence 25 % of the children born could have brown hair. The above-mentioned inheritance pattern is based on the Mendelian rules.
What Is the Role of DNA in Human Genetics?
DNA serves the following actions:
-
Replication.
-
Transcription.
-
Mutation.
Apart from DNA, the other genetic material is RNA (ribonucleic acid). RNA acts like the messenger of information, and unlike DNA, it cannot replicate itself.
-
Replication represents the ability of DNA to make copies.
-
Transcription describes the ability of DNA to transfer genetic information from DNA to RNA.
-
Whereas mutation represents the ability of DNA to alter the genetic structure, which leads to genetic variation. The DNA programs our appearance, behavior, and other unique personal features, resulting in a resemblance between parents and children.
The following sequential steps can explain the central dogma of molecular genetics:
-
The genetic information gets transferred from DNA to RNA.
-
The process that uses the information given by RNA to form protein.
-
The previously mentioned sequential steps produce all the unique characteristics that describe an individual. For example, if the DNA has to program for the height of an individual, then:
Firstly, DNA will collect all required sets of information about the size. Then, it will be transferred to the RNA by the process of transcription. After that, the mRNA (messenger RNA), which carries the information given by DNA, will transfer it to the RNA. This information will then be converted into a protein. These proteins, in the end, execute the DNA program and activate subsequent processes required for the development of the height of an individual. So, the primary genetic information is located inside the nuclear DNA, and a few small pieces of information are found in the mitochondrial DNA.
Why Do Identical Twins Have Different Behavior Patterns?
Researchers have come up with a concept that individuals who grow up in similar environments have similar behavioral patterns, but at the same point if these individuals are subjected to different conditions their behavior pattern gets differentiated from each other. Twins share a similar prenatal environment and their developmental conditions are also nearly similar. As they grow up they may share different peer groups and these peers are part of an unshared environment between the twins. So, as their immediate environment or in this case, their peers or friends are different, there is a high probability that these twins will have different or varied behavioral patterns.
What Is the Relation Between Parent- Child Relation and Genetics?
The characteristics of the parents and a child that are genetically influenced indirectly play an important role in a parent-child relationship. Researchers have found that in the majority of cases, the parents hold a warm and compassionate behavior towards the child but it is the child’s attitude or temperament that alters the parents' attitude towards them. The importance of the shared environment is highlighted by the researchers and these environmental factors influence the behavioral pattern.
Conclusion
Studies that work upon relating the genetic influence and environmental influences on behavior patterns and these factors control the social life of individuals. Inheritance determines the individual's characteristics, and DNA's ability to mutate is a platform for human evolution. Various researchers are currently studying the inheritance pattern, and this research work also focuses on locating the genes that help identify the cause of a particular disease. Genetic mapping is the latest advancement in the field of medical genetics.
