Plant Cytogenetics: Incomplete dominance ppt
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The document explains incomplete dominance in genetics, where neither allele is completely dominant, leading to a blend of traits in the heterozygous condition. It outlines the genotypic and phenotypic ratios in F2 generation as 1:2:1 and provides examples, such as flower color in snapdragons and coat color in horses. The document also includes assignments related to incomplete dominance in radishes and Andalusian fowls.
Plant Cytogenetics: Incomplete dominance ppt
- 1. B.SC. III YEAR: SEMESTER-VI GENETICS AND BIOTECHNOLOGY INCOMPLETE DOMINANCE Dr. Anjali Naik Head, Dept. of Botany SBES COLLEGE OF SCIENCE
- 5. EXPLANATION OF INCOMPLETE DOMINANCE • Deviation of Monohybrid inheritance. • Definition: When none of the two alleles, controlling the character, are completely dominant or recessive, both of them express phenotypically in F1 heterozygous condition and when their expression show uniform blending, it is called as Incomplete inheritance. • F2 has same genotypic and phenotypic ratio: 1:2:1 • Phenotypic ratio modified with 3 classes, instead 2, as seen in classic Mendelian Monohybrid inheritance and ratio gets modified as 1:2:1 • Example: Flower colour in Snapdragon, Mirabilis jalapa
- 6. HOW INCOMPLETE DOMINANCE CAN BE EXPLAINED? • Parents: phenotypes: Red flowered and white flowered. • Genotypes of parents: Red flowered – RR. 2. White flowered:WW • Gametes of Red cow: all gametes will have allele- R • Gametes of white bull:All gametes will have allele- W • Red flowered X White Flowered • RR X WW • F1 :All individuals will have RW genotype and Pink flowered • Selfing of F1 : RW X RW
- 7. 7 Male Parent Female parent R W R RR (Red) RW(Pink) W RW (Pink) WW(White) Punnett square Incomplete dominance for proportions of F2 F2 Genotypic ratio: RR 1: RW 2:WW 1 Phenotypic ratio: Red 25%: PINK 50%:White 25%
- 8. OTHER EXAMPLES OF INCOMPLETE DOMINANCE COAT COLOUR OF HORSES FEATHERS IN ANDULASIAN FOWLS
- 9. ASSIGNMENT ON INCOMPLETE DOMINANCE 1. In radishes, red and white are pure-breeding colors, while hybrids are purple. If a red radish is crossed with a white radish, what will be the phenotype of the F2 generation (assuming the F1 generation self-pollinates)? Show the Punnett Square. 2. In Andulasian fowls, black individuals (B) and white individuals (W) are homozygous. A homozygous black bird is crossed with a homozygous white bird.The offspring are all bluish-gray. Show the cross as well as the genotypes and phenotypes of the parents and offspring.