IB Biology D3.2 Definitions
This page contains our IB Biology definitions for D3.2. By learning each one of these definitions, you will fully cover the content for IB Biology 'Polygenic inheritance'.
carrier
An individual that is heterozygous for a genetic disease
co-dominance
An inherited genotype of two dominant alleles that express a joint phenotype
continuous variation
The division of characteristics into an infinite number of forms
discrete variation
The division of characteristics into a finite number of different groups
dominant allele
An allele who's phenotype is expressed over a recessive allele. Dominant alleles are capitalized (A)
genotype
The alleles than an organism contains to exhibit a characteristic
heterozygous
The presence of two different alleles (Aa)
homozygous
The presence of two of the same alleles (AA or aa)
linked genes
Genes that are on the same chromosome
locus
A specific position on a chromosome
mutagen
A substance capable of causing a mutation
mutation
A random change to the base sequence of a gene
non-linked genes
Genes that are on different chromosomes
phenotype
The characteristic physically exhibited by an organism
polygenic inheritance
The inheritance of multiple genes coding for a single characteristic
recessive allele
An allele who's phenotype is masked by a dominant allele. Recessive alleles are lowercase (a)
recombinant
A new combination of linked genes made via recombinatinon during crossing over in prophase I
segregation
The phenomenon of offspring inheriting one allele from each parent due to the formation of haploid nuclei during meiosis
sex-linked condition
A condition dependent on the sex of the individual because the allele is present on the X chromosome
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