Chapter 10 Flashcards
P generation
Two organisms that represent the start of a breeding experiment.
F1
first generation offspring. Often between two pure breeding parents.
Pure breeding
A line of organism that always produce offspring with the same phenotype when crossed with each other.
F2
Offspring from the cross of F1
Dominant
A phenotype that only one allel is required to be expressed.
Recessive
Phenotype that requires to alleles to be expressed
Homozygous
Genotype with twos genes of the same alleles from a single gene locus
Heterozygous
a genotype of two different alleles on the same gene locus.
Hybrid
The offspring of a cross between two plants or animal species. Heterozygous
Genotype
A specific combination of alleles for a particular gene locus.
Phenotype
A specific feature on an individual based on their genotype.
Mono hybrid cross
Two heterozygous combinations are used as parents.
Genotypes: 1:2:1
Phenotypes: 3:1
Autosomal
Genes located on autosomes (non-sex chromosomes)
In a test cross always……
Test the Unknown to a homozygous recessive.
Incomplete dominance (partial)
No clear dominance can get mixed.
Eg. Red flower ✖️ white flower
I red: 2 pink: I white
Codominance
Both alleles are fully expressed
Eb. Blood types
Ia Ib i
Multiple alleles
Three or more forms of genes are available for a trait but only two exist in a diploid cell.
Why test cross?
To see if an organism is heterozygous or homozygous.
If genes are linked.
Deadly combinations
Lethal alleles
When a homozygous trait is lethal
Dihybrid cross
A mating experiment between two organisms considering two traits. Unlinked
Eg. Phenotype always when crossing F1 9:3:3:1
linked genes
If a gene is linked the punnet square will only produce two phenotype so provided no crossing over.
Eg. DE. ✖️ de
de. de
Crossing over in linked chromosomes
Ratio frequencies are different of crossing over.
Polygenic inheritance / continuous variation
Many genes, wide range,
Eg height, skin colour
Discontinuous variation
Only a single gene is involved. Small range of discreet phenotype so.
Hemizygous
One copy only x
Polygenic inheritance / continuous variation
Many genes, wide range,
Eg height, skin colour
Discontinuous variation
Only a single gene is involved. Small range of discreet phenotype so.
Hemizygous
One copy only x
