Patterns of Inheritance (Punnett squares) Flashcards
Homologous Chromosomes definition
Each cell has a pair (two) of each chromosome, one derived from the mother and one from the father. The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci (location), but possibly different alleles.
Allele definition
Different versions of the same gene. Alleles are found at the same place on a chromosome, but do not necessarily contain the same information for the trait it codes for.
Homozygous definition
Homozygous (homo = same) is a word that refers to a particular gene that has identical alleles on both homologous chromosomes. It is referred to by two capital letters (e.g. BB) for a dominant trait or two lowercase letters (e.g. bb) for a recessive trait.
Heterozygous definition
Heterozygous (hetero = not same) is a word that refers to a particular gene that has non-identical alleles on both homologous chromosomes. It is referred to by one capital letter and one lowercase letter (e.g. Bb). The genotype contains both the dominant and recessive trait, but the phenotype will only show the dominant trait.
Genotype
The genetic constitution of an individual organism (e.g. BB, Bb or bb).
Phenotype definition
The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
Dominant definition
A dominant trait is the trait which affects the phenotype. It will mask the recessive allele if one of the chromosomes carries it.
Recessive definition
A recessive trait is the trait which will only affect the phenotype in homozygous individuals: you need both copies of the recessive trait to affect the phenotype. If one of the chromosomes carries the dominant allele, the recessive allele will be masked.
Explain Mendel’s experiment
Observed predictable inheritance patterns in traits (e.g., seed shape).
Bred pure lines and tracked traits across generations.
Identified dominant and recessive traits through patterns in offspring.
What is the Principle of dominance?
In a pair of traits, one (dominant) can mask the other (recessive).
What is the Principle of Segragation?
Organisms have two alleles for each trait, segregated in gamete formation.
When an organism makes gametes, each gamete receives just one allele which is selected randomly
What is the Principle of Independent Assortment
Genes for different traits assort independently during gamete formation.
The allele a gamete receive for one gene does not influence the allele received for another gene
What is heredity?
Heredity is the passing of traits from parent to offspring, traits are controlled by genes, the different forms a gene may have for a trait are called allele. There are 2 allele for every trait
