Genetic Bases of Development - Chromosome

Chromosomes are thread-like structures present inside the nucleus of every cell. They carry genes, which are the units of heredity that determine our characteristics.

• During fertilization, the sperm from the father and the ovum (egg) from the mother combine.
• Each contributes 23 chromosomes (half the total).
• The fertilized egg (called a zygote) then has 46 chromosomes (23 pairs).

• Each chromosome has smaller units called genes.
• Genes control hereditary traits like eye color, height, and blood type.
• They are made of DNA (Deoxyribonucleic Acid).

• Genes transfer traits from parents to offspring.
• This process is called heredity.
• Each child inherits a unique genetic combination from both parents.

• The concept that chromosomes and genes carry hereditary information was supported by the research of August Weismann (1889).
• He stated that these hereditary materials remain unchanged when passed from one generation to the next.

• Chromosomes are thread-like structures in cells that carry genes, the units of heredity.
• At conception, the sperm and egg each contribute 23 chromosomes, forming a zygote with 46.
• Genes, made of DNA, control traits like height, eye color, and blood type.
• Heredity is the passing of traits from parents to children through genes.
• August Weismann (1889) showed that genes carry hereditary information unchanged across generations.