Mendelian Genetics and DNA Synthesis

Study Notes

Phenotype: Observable traits.
Genotype: Genetic makeup.
Dominant Trait: Expressed with one allele.
Recessive Trait: Expressed only with two alleles.
Homozygous: Two identical alleles (e.g., BB or bb).
Heterozygous: Two different alleles (e.g., Bb).
Punnett Squares: Predict offspring trait probabilities.
- Example: BB (black) x bb (white) = 100% Bb (black) offspring.
First-Generation Offspring: Recessive traits can be hidden.
Probability in Genetics: Likelihood of specific outcomes.

DNA Base Pairing: A with T, C with G.
Codons: Three-base sequences coding for amino acids.
- Example: ACCTAGTTG codes for specific amino acids.

Incomplete Dominance: Traits blend (e.g., red + white = pink).
Codominance: Both traits are fully expressed (e.g., black + white = black and white feathers).
Multiple Alleles: More than two alleles exist, but individuals possess two. (e.g., blood types A, B, O).
Polygenic Traits: Traits influenced by multiple genes (e.g., human height).

Mutations: Changes in DNA sequence.
Substitution Mutation: One base is replaced.
- Example: A sex cell mutation can be inherited.
Genetic Disorders: Caused by mutations or chromosomal problems.
Karyotype: Visual representation of chromosomes, used to detect abnormalities.

Blood Typing: Blood types (A, B, AB, O) depend on alleles.
- Example: Type A + Type B parents can produce offspring of any blood type.
Pedigrees: Charts tracking trait inheritance through generations.

If a DNA sequence is ACCTAGTTG, what would the complementary DNA strand be? The provided text does not give the answer, but the complementary strand would be TGGATCAAC.
Explain the outcome of crossing a heterozygous tall pea plant (Tt) with a short pea plant (tt). The Punnett square would predict a 50% chance of tall offspring (Tt) and a 50% chance of short offspring (tt).
How do incomplete dominance and codominance differ? Incomplete dominance produces a blended trait, while codominance results in both traits being expressed fully.