1. Genetic Terms Flashcards
Gene
Sequence of bases on DNA molecule that codes for a proteins (polypeptide )
Resulting in a characteristic
Alleles
Different versions of the same gene
There can be many different alleles of a single gene - most plants and animals only carry 2 alleles of each gene - one from each parents.
What makes alleles different from each other ?
The order of the dna based - code for different versions of the same characteristic.
How are alleles represented ?
Using letters
Alleles for eye colour.
Brown - B - dominant
Blue - b - recessive
Pea plants seed shape.
Round - R - dominant
Wrinkled - r - recessive
Are humans haploid or diploid
Diploid
2 copies of each chromosome - one from each parents.
What position is the allele for each gene positioned ?
Fixed position
Loci
Or
Locus
Genotype
The genetic constitution
The different alleles an organism has
Phenotype
Expression of the genetic constitution and its interaction with environment.
Characteristics an organism has as a result of both its genes and effect the environment has on the genes
Dominant allele
Always expressed in phenotype even when there’s only 1 copy
Capital letter
Recessive alleles
Characteristics that only appear in the phenotype if 2 copies are present
Lower case letters
Co-dominant alleles
When alleles are both expressed in phenotype because either one is recessive.
Example of codominance alleles
Horse has alleles for white / coloured hair.
Niether one is recessive.
Horse has copy of each alleles and will have a Roan coat .
Mixture of hair colours
At each locus in a diploid organism, what can the genotype be ?
Homozygous
Heterozygous
