Human Growth and Development

Gene-Environment Interactions

A person’s environment can influence their genetics in ways that are unpredictable. Researchers study twins and adopted children to understand how genes and environment shape traits. Studying Twins ●​ Identical (Monozygotic) Twins: >​ Come from one fertilized egg that splits >​ Share 100% of their genes ●​ Fraternal (Dizygotic) Twins: >​ Develop from two separate eggs fertilized at the same time >​ Share about 50% of their genes, like regular siblings Twin and Adoption Studies ●​ Twins Separated at Birth: ＞ ​ Same genetics, but different environments ＞ ​ Helps determine which traits are inherited vs. shaped by surroundings ●​ Adopted Children: ＞ ​ Comparing them to biological vs. adoptive parents reveals whether traits are influenced more by genetics (nature) or upbringing (nurture) These studies contribute to the nature vs. nurture debate, helping scientists understand the balance between heredity and environment in human development. Genetic Disorders Genetic disorders are caused by abnormalities in genes or chromosomes. A chromosomal error occurs when there is a mistake in the number of chromosomes, leading to missing or duplicated DNA. A mutation occurs when there is a permanent change in a gene or a segment of DNA. These abnormalities can lead to a variety of physical and cognitive problems.

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