Summary
Highlights
Genetics is defined as the study of heredity, focusing on the expression of traits and how they are passed down through generations. Humans have observed and utilized this inheritance for thousands of years in breeding plants and animals.
The scientific understanding of inheritance began in the mid-19th century. Gregor Mendel's 1865 studies on pea plants identified 'factors' (later known as genes) that influence trait expression, laying the foundation for modern genetics.
Humans have 20,000 to 25,000 genes, collectively called a genome, which determines traits by influencing cellular factors. Genetic information is stored in the cell's nucleus within chromosomes, which contain DNA. DNA is a double helix made of nucleotides (sugar, phosphate, and bases: thymine, adenine, guanine, cytosine). These DNA segments are genes, carrying the coding for inherited traits. Each cell's DNA, if unraveled, would be over six feet long.
The Human Genome Project, launched at the turn of the 21st century, successfully identified about 99% of the human genetic sequence. Discoveries in genetics have opened up vast opportunities in medicine, such as genetic testing and gene manipulation. However, these advancements also bring risks and ethical questions that will shape the future of genetic understanding.