Genetic Crosses and Heredity Flashcards
Gametes
Gametes are haploid cells that are capable of fusion
Fertilisation
Fertilisation is the union of two gametes to form a single cell called a zygote
Alleles
Alleles are different (or alternative) forms of the same gene
Locus
The locus of a gene is its position on a chromosome
Dominant
Dominant means the allele that prevents recessive allele from being expressed
Recessive
Recessive means the allele is prevented from being expressed by a dominant allele
Genotype
Genotype means the genetic make-up of an orgnism, i.e. the genes that are present
Phenotype
Phenotype means the physical make-up, or appearance, of an organism
Progeny
Progeny refers to offspring that are produced
Homozygous
Homozygous means that two alleles are identical
Heterozygous
Heterozygous means that the alleles are different
Punnett Square
A punnett square is a grid used to show the ratio of the genotypes of the progeny in a genetic cross
Incomplete Dominance
Incomplete dominance means that neither allele is dominant or recessive with respect to the other. Both alleles are equally expressed in the heterozygous genotype to produce an intermediate phenotype
Pedigree
A pedigree is a diagram showing the genetic history of a group of related individuals
The Law of Segregation (Mendel’s First Law)
States that inherited characteristics are controlled by pairs of alleles. These alleles segregate (or separate) from each other at gamete formation, with only one member of the pair being found in each gamete
