genetics Flashcards
define genotype
Genetic instructions inherited from both parents at a particular gene locus
define phenotype
Characteristics that results from the expression of an organisms genotype
define homozygous
a gene that has identical alleles on both homologous chromosomes
define heterozygous
When a gene contains two different alleles
define alleles
Alternate forms of a gene for a particular characteristic. .each allele is characterised by a slightly different nucleotide sequence. you have a particular combination of alleles in your genotype
define dominate
refers to a trait that requires only one allele to to be present for its expression
define recessive
Refers to a trait that will only be expressed in the absence of allele for dominate trait
define carrier
A person who is heterozygous but carries the allele for the recessive trait
what does a capital letter represent on a punnet square ?
it represents a dominant allele
what do letters represent in punnet squares
allels
what is a punnet square?
a punnet square is a diagram showing the allele combination that might result from a genetic cross between two parents
where is the alleles of the first parent placed
the top of the square
where is there alleles of the second parent placed
across the side of the square
what does a lower case letter represent
a recessive trait
