Variations in Mendel's Theories Quiz 7D Variations in Mendel's Theories

Variations in Mendel's Theories Incomplete dominance Codominance Multiple gene inheritance Sex-Linked traits

Incomplete dominance a type of inheritance in which the genes expressing a particular characteristic are neither dominant or recessive; two traits combine or blend together to produce a different trait (a blend of two traits) (when offspring of two homozygous parents show an intermediate phenotype)

Incomplete dominance example: flower color in snapdragons & four o’clock flowers

Codominance In codominance the dominant and the recessive traits are both expressed. Example: roan cattle

Codominance In incomplete dominance neither allele is fully dominant. This is different from codominance, in which both alleles are fully expressed, resulting in organisms that display the characteristics of both parents.

Codominance In codominance, both alleles are expressed independently and are uniquely recognizable.

multiple gene inheritance multiple gene inheritance (also called Polygenic Inheritance)- two or more genes producing a single trait (examples: hair color, skin color, eye color, height, intelligence, body build, etc.)

How to work incomplete dominance problems. purebred red X purebred white carnations

How to work incomplete dominance problems. Step 1: possible pheotypes and genotypes Pheno Geno use two different letters to represent genes use lower case letters red white pink rr ww rw purebred red X purebred white carnations

How to work incomplete dominance problems. Step 2: parent genotypes w w purebred red X purebred white carnations

How to work incomplete dominance problems. Step 3: fill in possible genotypes of offspring w w r w r w w r w r purebred red X purebred white carnations

How to work incomplete dominance problems. Step 4: Genotipic ratio Phenotipic ratio w w r w r w w r w r red:white:pink rr:ww:rw 0:0:4 purebred red X purebred white carnations