Inheritance Flashcards
What is a gene?
A length of DNA that codes for one polypeptide
What is an allele?
One version of a particular gene
What is a locus?
The location of a gene on a chromosome
What is the genotype?
The alleles possessed by an organism
What is the phenotype?
The characteristics of an organism often resulting from an interaction between it’s alleles and the environment
What is a dominant allele?
An allele is said to be this when it’s effect on the phenotype of a heterozygote is identical to it’s effect in a homozygote
What is a recessive allele?
An allele is said to be this if it is only expressed when there is no dominant allele present
What is a codominant allele?
Alleles are said to be this when both alleles have an effect on the phenotype of a heterozygous organism
What does being heterozygous mean?
Having two different alleles of a gene
What does being homozygous mean?
Having two identical alleles of a gene
What would the phenotypic ratio be in a monohybrid cross?
3:1
What is a test cross?
A breeding experiment that determines an organism’s genotype by crossing it with an organism that has a known genotype (homozygous recessive)
What does having multiple alleles mean?
More than two versions of the gene
What is an autosome?
A chromosome in a eukaryotic cell that is not a sex chromosome
What is the phenotypic ratio for two heterozygotes crossed with codominance?
1:2:1
What does a monohybrid cross do?
Look at one trait
What does F1 mean?
First filial generation
What does F2 mean?
Second filial generation
What does a dihybrid cross do?
Look at two traits together
What is a linked gene?
More than one gene on the same chromosome
What would having linked genes mean for the offspring?
They are more likely to inherit the trait as it is linked
Why would likelihood of inheriting the trait increase if they are on the same gene?
It doesn’t rely on crossing over
Why would likelihood of inheriting the trait decrease if they are not on the same gene?
Relies on crossing over
What is the phenotypic ratio for two heterozygotes in a dihybrid cross?
9:3:3:1
