Introduction to genetics
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This document summarizes basic genetics concepts including that alleles can be dominant or recessive, represented by uppercase or lowercase letters respectively, and that an individual's genotype describes their genetic makeup while their phenotype describes observable characteristics. It also outlines that genetic crosses involve parent (P) and offspring (F1, F2) generations, that mutations originate genetic variation as harmful, beneficial or neutral changes in DNA, and that Mendel's theory demonstrated traits can skip generations as alleles separate and gametes fuse randomly during reproduction.
Introduction to genetics
- 1. Alleles Dominant - expressed when paired with a different allele Represented by an uppercase letter Recessive - no effect when paired with a dominant allele Represented by a lowercase letter
- 2. Alleles in an Individual Homozygote - same two alleles (AA or aa) Heterozygote - two different alleles (Aa) Genotype - the genetic makeup Phenotype - observable characteristics
- 4. Genetic Cross When two individuals are mated P generation - parent generation F 1 generation - first generation F 2 generation - second generation
- 5. Gene Mutations Different alleles originally arose from a mutation Mutation - change in DNA that makes up a gene Mutations can be: Harmful Beneficial Neutral
- 6. Basic Patterns of Inheritance Mendel started with true breeding plants Recessive trait skipped a generation
- 7. Summarizing Mendel’s Theory Alternative versions of genes (alleles) cause variation Offspring inherit one copy of a gene from each parent Alleles are dominant if they determine the phenotype Two copies of a gene separate in meiosis Gametes fuse randomly