Key definitions Flashcards
Gene
A sequence of bases on a DNA molecule that codes for a protein, which results in a characteristic
Allele
A different version of a gene, that code for different versions of the same characteristic
Genotype
The genetic constitution of an organism, the alleles it has
Phenotype
The expression of the genetic constitution and it’s interaction with the environment, the characteristics
Dominant
An allele whose characteristic appears in the phenotype even when there’s only one copy
Recessive
An allele whose characteristic only appears in the phenotype if two copies are present
Codominant
Alleles that are both expressed in the phenotype, neither is recessive
Locus
The fixed position if a gene on a chromosome
Homozygote/homozygous
An organism that carries two copies of the same allele
Heterozygote/heterozygous
Am organism that carries two different alleles
Carrier
A person carrying an allele which is not expressed in the phenotype but can be passed on to offspring
Diploid
Two sets of chromosomes
Haploid
One set of (unpaired) chromosomes
Phenotypic ratio
The ratio of different phenotypes in offspring
Dihybrid cross
A diagram which shows the changes of offspring inheriting certain combinations of characteristics, like two different genes at the same time
