Chapter 5.1 Genetics Introduction ✓ Flashcards
Define dominant
A phenotype that requires only one copy of its allele for it to be expressed in an individual
Define genetics
Is the study of how inherited traits are passed from one generation to the next through coded chemical instructions in DNA.
Define trait
An inheritable characteristic
Define inheritance
The passing of traits from parents to offspring
Define gene
The stored set of instructions for a protein found on a specific locus (position) on a chromosome
Define allele
Alleles are different forms of a gene
Define pure-breeding
A line of organisms that always produce offspring with the same phenotype when crossed with one another
Define homozygous
Possessing two identical alleles of a gene
Define heterozygous
Possessing two different alleles of a gene
Define autosomal trait
Trait inherited on an autosome (a chromosome that is not a sex chromosome)
Define sex-linked trait
Traut inherited on a sex chromosome (X or Y)
Define punnett square
A table that displays all the possible offspring genotypes that can be produced at fertilisation.
Define first filial generation
-The first generation of offspring produced from a cross between two parents
-The word filial means son or daughter
Define second filial generation
Offspring of the F1 generation
What does a phenotype describe?
An observable trait/characteristic of an individual
Define locus
It is a specific, fixed position on a chromosome where a particular gene or genetic marker is located
Distinguish between a locus, a gene and an allele
A locus (or loci, plural) is the actual location of the gene on a region of a chromosome. An allele is a different form of a gene at a particular locus.
A gene is a set of instructions that specifies a structure of a protein
Define genotype and phenotype
An organism’s genotype is the set of genes that it carries. An organism’s phenotype is all of its observable characteristics
Define parental generation (P) and what generation is their offspring?
Two individuals or lines that represents the start of a breeding experiment; their offspring are the F1 generation
Define the P, F1 and F2 generations
-P generation (Parental generation) is the original pair of parents at the start of a genetic cross experiment.
-F1 generation (First filial generation) is the P generations offspring
-F2 generation (Second filial generation) is the F1 generations offspring
Determine the phenotype ratio for the offspring of a homozygous tall pea plant crossed with a heterozygous tall pea plant. Show your working out in a Punnett square.
