Gene Expression and Inheritance Quiz

Gene Expression and Inheritance

• Alleles: Different versions of a gene, controlling traits. Examples include V1 (dominant, high silk flexibility) and V3 (recessive, no silk).
• Genotype: The organism's genetic makeup (e.g., V1V1, V1V3, V3V3).
• Phenotype: The observable trait (e.g., high silk flexibility, no silk), determined by the genotype.
• Dominant Traits: Expressed even with only one copy of the dominant allele present.
• Recessive Traits: Expressed only when two copies of the recessive allele are present.
• Homozygous: Having two identical alleles for a gene.
  • Homozygous Dominant: Two copies of the dominant allele (e.g., V1V1).
  • Homozygous Recessive: Two copies of the recessive allele (e.g., V3V3).
• Heterozygous: Having two different alleles for a gene (e.g., V1V3).
• Punnett Squares: Tools used to predict possible genotypes of offspring from parents with known genotypes. A cross between two V1V3 spiders has a 25% chance of V1V1, 50% chance of V1V3, and a 25% chance of V3V3 offspring.
• Autosomal Inheritance: Passing traits not linked to sex chromosomes (Y/X).
• Mendelian Genetics: Rules governing trait inheritance. Dominant traits mask recessive ones when both are present.

Silk Production Example

• V1 allele: Causes high silk flexibility (dominant).
• V3 allele: Causes no silk (recessive).
• Genotype-Phenotype Relationship: Genotypes (V1V1, V1V3, V3V3) determine corresponding phenotypes (high silk flexibility, high silk flexibility, no silk respectively).