Gregor Mendel: The Father of Genetics
Why did Mendel join the monastery?
He joined for financial stability and educational access. The monastery provided him the time, space, and resources to study and conduct scientific research.
What was Mendel’s former education?
He studied at the University of Vienna, where he learned mathematics, physics, and biology, shaping his analytical approach to science.
What hobbies did Mendel have?
Mendel enjoyed gardening, beekeeping, and conducting plant experiments, especially studying how traits passed from one generation to another.
Why a mathematical approach to biology?
His training in mathematics and physics led him to analyze biological inheritance using ratios, patterns, and statistics.
Why did he choose pea plants?
Pea plants had easily observable traits (e.g., flower color), reproduced quickly, self-pollinated or could be cross-pollinated, and produced many offspring for analysis.
Self-fertilization vs. Cross-fertilization?
Self-fertilization: A plant uses its own pollen.
Cross-fertilization: Pollen comes from another plant.
Mendel’s First Two Experiments
First: Crossed tall and short plants. The F1 generation was all tall. The F2 generation showed a 3 tall:1 short ratio.
Second: Examined two traits. The F2 generation displayed a 9:3:3:1 ratio, proving traits sorted independently.
Why “Father of Genetics”?
He was the first to identify predictable patterns of heredity using controlled experiments and mathematics, forming the basis of genetics.
Mendel’s Famous Teachers?
Christian Doppler (Doppler Effect, physics) and Franz Unger (botany) both influenced his scientific thinking.
Why Observed ≠ Theoretical Ratio?
Random chance, sample size, and environmental factors can cause results to differ from expected ratios.
Monohybrid vs. Dihybrid Cross?
Monohybrid: One trait is studied (e.g., color).
Dihybrid: Two traits are studied together (e.g., color and shape).
When did he form the Law of Dominance?
During monohybrid crosses, he noticed that one trait (dominant) always masked the other (recessive) in F1 plants.
What shows the Law of Independent Assortment?
Dihybrid crosses, where different traits sort independently into gametes, shown by the 9:3:3:1 ratio in F2.
When do alleles recombine?
After segregation during gamete formation, alleles recombine during fertilization when egg and sperm join.
Genotype vs. Phenotype?
Genotype: Genetic code (e.g., Bb, TT).
Phenotype: Physical expression (e.g., brown fur, tall).
Are all phenotypes visible?
No; some are internal, like blood type or enzyme levels, and cannot be seen with the eyes.
Homozygous Dominant vs. Recessive?
Homozygous Dominant: Two dominant alleles (e.g., TT); the trait is expressed.
Homozygous Recessive: Two recessive alleles (e.g., tt); the trait shows only if no dominant allele is present.
What is heterozygous?
An organism with one dominant and one recessive allele (e.g., Tt), usually showing the dominant trait.
Why wasn’t Mendel famous in his time?
His ideas were too advanced and misunderstood. They weren’t recognized until after his death around 1900.
What are non-Mendelian genetics?
Inheritance patterns that do not follow Mendel’s laws, such as incomplete dominance, codominance, multiple alleles, polygenic traits, and gene linkage.