MENDELIAN GENETICS | Grade 8 Science Quarter 4 Week 3

Summary

Key Points

• Dominant alleles are expressed and represented by capital letters, while recessive alleles are masked by dominant ones and represented by small letters. 0:47
• Homozygous organisms have two identical copies of a gene, while heterozygous organisms have two different copies. 1:41
• Genotype refers to an organism's genetic makeup, while phenotype is the observable physical trait. 2:29
• Gregor Mendel developed the laws of dominance, segregation, and independent assortment, establishing him as the father of genetics. 3:58
• Mendel experimented with pea plants, studying traits such as seed shape, seed color, flower color, and stem length. 4:26
• A Punnett square is a tool used to predict the possible genetic outcomes of a cross between two individuals. 4:49
• When crossing a homozygous dominant parent with a homozygous recessive parent, all offspring (F1 generation) will be heterozygous and display the dominant phenotype. 6:47
• The F1 generation represents the first filial generation, and the F2 generation is produced by crossing individuals from the F1 generation. 6:49
• Crossing two heterozygous individuals (F1 generation) results in an F2 generation with a genotypic ratio of 1:2:1 (homozygous dominant: heterozygous: homozygous recessive) and a phenotypic ratio of 3:1 (dominant: recessive). 8:10