Genetics Test Study Guide

gene
the DNA that codes for a trait
allele
the different forms of the same trait
Dominant Allele
the stronger allele, only need one cope to show the trait
Recessive allele
the weaker allele, need two copies to show the trait
Genotype
actual genes for a trait
Phenotype
the physical appearance of a trait
Homozygous
two of the same alleles
Homozygous dominant
AA
Homozygous recessive
aa
Heterozygous
two different alleles
Law of Segregation
Traits come in pairs
Alleles separate into gametes during reproduction
Law of Independent Assortment
One trait does not affect the inheritance of another
Mendel’s Laws
Law of Segregation
Law of Independent Assortment
Di-hybrid Cross Genotype Ratio
Dom,Dom: Dom, rec: rec,Dom: rec, rec
Sex – linked Traits
Gene is carried on X or Y chromosome
Rule of Multiplication
Probability that 2 or more events will occur the same way
“and”
Rule of Addition
Probability that an event will occur in 2 or more ways
“or”
Co-dominance
when both alleles are dominant; you see both phenotypes
Incomplete Dominance
when neither allele is completely dominant over the other; you see the intermediate
Blood Groups
Example of Co-dominance
Red flower plus white flower = pink flower
Example of Incomplete Dominance