Genetic Bases of Development

Every person’s growth and behavior are influenced by two factors: heredity and environment. Heredity means the traits we get from our parents through genes. Environment means everything around us — family, school, society, and experiences. Both heredity and environment work together to shape who we are. Development is not the result of one alone, but the interaction of both.

Heredity is the process by which parents pass their physical and mental traits to their children. These traits are carried by genes, which are tiny units of DNA. DNA is stored in chromosomes, and every human has 46 chromosomes — 23 from the father and 23 from the mother.

Genes decide traits such as:

• Height
• Eye color
• Intelligence
• Behavior patterns

Some traits come from a single gene, while others depend on many genes combined.

Genes decide our potential, but the environment controls how much of that potential is expressed.
A person may be born with a certain ability, but without a good environment, that ability might not develop properly.

Examples:

• A child may have the genes to be tall, but poor nutrition can prevent growth.
• A child may inherit musical talent, but it can only improve with practice and training.

Environment includes:

• Family and upbringing
• School and education
• Friends and social life
• Nutrition, climate, and culture

Our growth happens through the interaction between heredity and environment.

• If heredity remains the same but environment changes, the person will grow differently.
• If the environment remains the same but heredity differs, the person will also be different.

This is why even children of the same parents are not exactly alike. They share some genes but also have unique experiences.

• Before birth, life starts when a male cell (sperm) from the father joins a female cell (ovum) from the mother.
• This forms a zygote, which contains 46 chromosomes with genetic material from both parents.
• This is how physical and psychological characteristics are passed down to the next generation.

• Francis Galton was a scientist who studied heredity.
• He believed that intelligence, abilities, and personality can be passed down from one generation to another.
• He said that children’s traits are connected to those of their parents and grandparents.

• Both heredity and environment influence our development.
• Genes carry information from parents to children.
• The environment helps genes to show their effect.
• Development is the result of the interaction between heredity and environment.
• Each person is unique because of differences in genes and experiences.