Heredity and Variation
HEREDITY AND VARIATION
- Genetics is a branch of biology that focuses on the inheritance and variation of traits from parents to offspring.
- Inheritance is the process through which characteristics are passed from parents to their progeny, forming the basis of heredity.
- Variation refers to the extent to which offspring differ from their parents in terms of traits.
- Humans have understood the role of sexual reproduction in generating variation since ancient times, dating back to 8000-1000 B.C.
- Early humans harnessed naturally occurring variations in wild plant and animal populations for selective breeding to obtain organisms with desirable traits.
- It's important to note that our ancestors had limited scientific understanding of the mechanisms underlying inheritance and variation.
- In the mid-nineteenth century, Gregor Mendel conducted groundbreaking experiments on garden peas (1856-1863) that led to the understanding of inheritance in living organisms.
- Mendel's experiments marked the first application of statistical analysis and mathematical logic to biological problems, bringing a scientific approach to genetics.
- Mendel's extensive sampling size and rigorous experimentation methods lent credibility to his findings.
- Mendel's work demonstrated general rules of inheritance, rather than mere conjecture, by confirming his inferences across successive generations of pea plants.
- He focused on traits with two opposing forms, such as tall or dwarf plants and yellow or green seeds, which allowed him to establish a foundational framework for inheritance.
- Mendel's experiments involved artificial pollination and cross-breeding using true-breeding pea lines. True-breeding lines exhibited stable trait inheritance over multiple generations.