7.1 Inheritance Flashcards
Define genotype.
The genetic constitution of an organism
Define phenotype.
The expression of an organism’s genetic constitution
What is an allele?
Different forms of a particular gene found at the same locus on a chromosomes
How many alleles do diploid organisms carry per gene?
Two
What is meant by a dominant allele?
An allele whose characteristic will always appear in the phenotype, whether one or two are present
What is meant by a recessive allele?
An allele whose characteristic will only appear in the phenotype if no dominant allele is present, meaning two must be present
What is meant by codominant alleles?
Two dominant alleles that both contribute to the phenotype
What is meant by homozygous?
Both alleles are the same, dominant or recessive
What is meant by heterozygous?
Both alleles are the different, one is dominant and one is recessive
Define monohybrid inheritance.
Where one phenotypic characteristic is controlled by a single gene
Define dihybrid inheritance.
Where two phenotypic characteristics are determined by two different genes present on two different chromosomes at the same time
What is meant by sex-linkage?
Where an allele is located on one of the sex chromosomes, meaning its expression depends on the sex of the individual
Why are males more likely to express recessive sex-linked alleles?
Most are located are located on the X chromosome so males only get one copy of the allele and will express the characteristic even if its recessive
Females get two copies of the allele
Which parent do males inherit sex-linked characteristics from?
Maternal parent as the Y chromosome can only come from the paternal
