genetic and inheritance Flashcards
(12 cards)
Mendelian genetics
Law of seggregation: each parent passes only one allele per gene to offspring
law of independant assortment: genes for different traits assort indepedantly during gamete formation
dominant vs recessive alleles: dominant alleles mask recessive ones in heterozygous individuals.
punnet squares and probability
used to predict offspring genotype probabilities
monohybrid cross: single trait inheritance
Dihybrid cross: inheritance of two traits simultaneously
Non-mendelian inheritance
Incomplete dominance: blend phenotype ( red + white = pink)
codominance: both alleles are fully expressed ( AB blood type)
polygenic inheritance: traits controlled by multiple genes ( height, skin color)
epistatis: one gene masks the expression of another
pleiotrophy: one gene affects multiple traits ( sickle cell disease)
enviromental influence : gene expression can be affected by external factors
sex-linked traits
genes on the X chromosome affects males more often because they only have one X
ex: color blindness, hemophilia, duchenne muscular dystrophy
pedigree Analysis
used to track inheritance of traits across generations
can determine if a trait is dominant,recessive, autosomal or sex-linked
Explain the Law of Segregation and how it relates to meiosis.
Law of Segregation: Each gamete receives only one allele from each gene, ensuring variation in offspring.
If two heterozygous parents for a dominant trait (Rr x Rr) mate, what are the expected genotypic and phenotypic ratios in the offspring?
Rr x Rr Genotypic Ratio: 1:2:1 (RR:Rr:rr), Phenotypic Ratio: 3:1 (dominant:recessive).
A man with blood type A (genotype AO) has a child with a woman with blood type B (genotype BO). List the possible blood types of their child.
Possible blood types: A, B, AB, O.
draw a Punnett square for a cross between a heterozygous round (Rr) pea plant and a homozygous wrinkled (rr) pea plant, and state the expected ratios.
Punnett Square for Rr x rr:
50% heterozygous (Rr) - round, 50% homozygous recessive (rr) - wrinkled.
Describe an example of pleiotropy and how one gene can cause multiple effects in an organism.
pleiotropy: one gene influencing many traits ; Sickle cell , heterozygous gives malaria resistance but homo leads to many effects
A man with red-green color blindness (X-linked recessive) marries a woman who is a carrier for color blindness. What are the chances of having a color-blind son? A color-blind daughter?4
Color-blind son: 50%, Color-blind daughter: 25%.
A father with Duchenne muscular dystrophy (X-linked recessive) has children with a mother who is not a carrier. Will their sons or daughters inherit the disease? Explain why.
Duchenne Muscular Dystrophy: Sons won’t inherit (Y from father), but daughters will be carriers.
