Unit 2-Variation And Inheritance Flashcards
Differences between all the individuals in a species
Variation
Type of variation in which there are two or more distinct groups, with no values in between
Discrete variation
Type of variation in which there is a wide range of values
Continuous variation
Example of discrete variation
Eye colour Blood Type Hair Colour
Example of continuous variation
Height Shoe size Hand Span
Term for several genes working together to produce continuous variation
Polygenic
Short section of a chromosome that has the genetic information for a particular characteristic
Gene
Different forms of a gene
Allele
The most common type of variation
Polygenic and continuous
The appearance of an organism for a characteristic
Phenotype
Alleles an organism has for a particular characteristic - usually written as capital or small letters
Genotype
Allele whose effect always shows in the phenotype
Dominant
Allele which is not dominant - its effect only shows when the cell does not have a dominant allele
Recessive
When an individual has the same alleles for a characteristic (bb or BB)
Homozygous
One dominant and one recessive allele for a feature
Heterozygous
Symbol for the parents in a genetic cross
P
Symbol for the first generation in a genetic cross
F1
Symbol for the second generation in a genetic cross
F2
Phenotype ratio from a cross between a heterozygous parent and a homozygous recessive parents
1:1
Phenotype ratio from a cross between two heterozygous parents
3:1
The number of 120 Drosophila flies from two heterozygous parents that would be predicted to have the recessive characteristic (3:1 ratio)
30
The number of 120 Drosophila flies from two heterozygous parents that would be predicted to have the recessive characteristic (3:1 ratio)
30
The reason why the predicted and the actual results from a genetic cross are often not the same
Fertilisation is a random process
The reason why the predicted and the actual results from a genetic cross are often not the same
Fertilisation is a random process
