Incomplete Dominance & Co-Dominance Flashcards
What is the Principle of Independent Assortment?
Genes for different traits segregate independently during formation of gametes (meiosis)
This accounts for the high diversity in traits seen in plants, animals, and other organisms.
What does the Law of Segregation state?
Alleles separate during meiosis; gametes only get one allele each of a particular gene.
Define Incomplete Dominance.
A form of intermediate inheritance where one allele is not completely expressed over its paired allele, resulting in a third phenotype.
What is the phenotypic ratio for a cross between two heterozygous pink carnations?
1 Red : 2 Pink : 1 White
What is Co-Dominance?
A form of dominance where both alleles are fully expressed in a heterozygote.
What is an example of Co-Dominance in cattle?
Roan coat color.
What are the possible blood types and their corresponding genotypes?
- Type A: I^A I^A or I^A i
- Type B: I^B I^B or I^B i
- Type AB: I^A I^B
- Type O: i i
What is the Rh factor?
A protein on red blood cells that determines blood compatibility.
What happens when the wrong blood type is transfused?
The recipient’s immune system attacks the foreign blood cells, leading to hemolysis.
Define polygenic traits.
Traits produced by the interaction of many genes.
What determines gender in humans?
The 23rd pair of chromosomes, which are sex chromosomes.
What are sex-linked traits?
Inheritance from a gene located on one of the sex chromosomes.
What is X-Linked Recessive inheritance?
A trait that is expressed in individuals with genotype X^a X^a or X^a Y.
What is an example of an X-linked recessive disorder?
Colorblindness.
What is the difference between Incomplete Dominance and Co-Dominance?
Incomplete Dominance results in a blending effect, while Co-Dominance shows both traits equally expressed.
Fill in the blank: The Y chromosome has very few genes that cause an observable phenotype, so there is not a lot of _______ linkage.
Y-linked
What is the genotypic ratio for a cross between a Roan coat and a Red coat?
1 C^R C^R : 1 C^R C^W
What is the importance of the Rh factor in pregnancy?
Rh-negative mother with an Rh-positive baby can cause complications.
True or False: The ABO blood group system is an example of Co-Dominance.
True
