patterns of inheritence

Genetic variation arises through sexual reproduction, which combines genetic material from two parents.

Definition of Phenotype: The physical characteristics of an organism that can be observed (e.g., color, height, etc.).
Definition of Genotype: The genetic makeup or combination of alleles inherited from parents.
Example: A purebred green seed pea plant has the genotype gg - both alleles are the same and recessive (green is recessive for seed color).
Hybrid Genotype: A yellow seed phenotype can have two possible genotypes: GG (homozygous dominant) or Gg (heterozygous).

Homozygous (homo- = same): An organism with two identical alleles for a trait.
- Homozygous Dominant: Both alleles are dominant (e.g., GG for yellow seeds).
- Homozygous Recessive: Both alleles are recessive (e.g., gg for green seeds).
Heterozygous (hetero- = different): An organism with one dominant allele and one recessive allele (e.g., Gg).

Genotype: Refers to the genetic makeup of an organism.
Phenotype: Refers to the visible physical characteristics.
Reading Check: Compare and determine that genotype is genetic makeup and phenotype is physical manifestation.

Genotype Description for dd: Homozygous recessive.
Probability of Seed Colors: If comparing the probabilities, expect a 50% chance for both yellow and green seeds based on genetic composition.
Mendel's Experiments: Important for advancing knowledge of genetics due to his systematic observations on traits (size, shape, color) across generations.
Predicting Outcomes in Crosses: Tall stem length with genotype predictions based on parental combinations (e.g., Tt x tt).
Dominant vs. Recessive Influences: If dominant and recessive parents are involved, the dominant trait would likely prevail.

Mendel discovered that the dominant seed color in peas is yellow, while the recessive is green.
Mendel's Influence: His work challenged previous beliefs about trait inheritance that suggested traits were blended rather than distinct.

Definition of Probability: A number indicating the likelihood of a specific event, such as genetic inheritance, occurring.
Coin Toss Example: Probability of heads is 1 out of 2 (50%), each toss is independent.
Probability of Traits: When comparing traits, laws of probability predict the expected offspring characteristics (example of multiple children of the same sex).
Questions to Answer: How does this relate to observed genetic traits? Apply knowledge through interaction and calculations.

Mendel's Methodology: Examined pea plant traits through systematic cross-pollination.
Filial Generations: First Filial Generation (F1) offspring express dominant traits, while Second Filial Generation (F2) reveals both dominant and recessive traits (3:1 ratio).

Trait List: Seed shape, seed color, flower color, pod position, pod color.
Mendel's Key Findings:
- For traits observed, dominance is not a mixture but rather separate expressions based on inheritance.

Change in Terminology: 'Factors' described by Mendel are now called genes or alleles (different forms of a gene).
Dominant vs. Recessive Alleles: Dominant alleles express traits while recessive traits remain hidden unless two recessive alleles are present.

Analyze what contributes to visible traits in offspring, looking for dominant and recessive patterns established historically in genetic studies.
Discuss implications of Mendel’s work on current understandings of heredity and traits.

Mendel’s methodology was revolutionary due to his precise collection and analysis of data on hereditary traits.

Understanding heredity and genetic variation relies on the foundational principles established by Gregor Mendel, whose methods in studying pea plants provided critical insights into inheritance patterns that continue to influence modern genetics.