Heredity is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. Through heredity, variations between individuals can accumulate and cause species to evolve by natural selection. The study of heredity in biology is genetics.
Identical twins have exactly the same DNA, but they are not exactly alike. Each twin has his or her own personality, talents, likes, and dislikes. There are even diseases that appear in one twin but not the other, including arthritis, diabetes, autism, schizophrenia, cancer, and many others. The differences between identical twins don’t come from DNA—they all come from external factors.
Scientists often study twins to understand how genes and the environment work together to affect traits. They compare traits in identical twins, who have identical DNA, and fraternal twins, who share half their DNA, just like any siblings. If a characteristic appears more frequently in identical twin pairs than in fraternal twin pairs, then it has an inherited component.
5 heredity examples
- Eye colour
One of the most common examples. The brown colour is the common type but blue eyes and other variants are due to mutation of the brown eye colour gene. Two blue eyed parents will always give birth to a blue eyed baby.
- Widows Peak
It refers to the v-shaped hair line which is dominant compared to straight hairline.
Free earlobe is dominant over attatched ones. It is a notable physical feature.
- Chin Cleft
It is another subtle example of inheritance where cleft chin is dominant over non-cleft chin.
Cheek dimples when present, show up when a person makes a facial expression, such as smiling, whereas a chin dimple is a small line on the chin that stays on the chin without making any specific facial expressions. Dimples may appear and disappear over an extended period; a baby born with dimples in their cheeks may lose them as they grow into a child due to their diminishing baby fat. They are often associated with youth and beauty (e.g. Chinese culture believes that cheek dimples are a good luck charm) and are seen as an attractive quality in a person’s face, accentuating smiles.