Genes, Traits & Alleles

Learning Target Genes encode proteins that produce a diverse range of traits….

The same gene can have many versions A gene is a segment or locus on a chromosome that determines a specific trait. Each chromosome in a pair encode for the same gene but provide different traits. These chromosome pairs (one from each parent) are called homologous chromosomes

Genes influence the development of traits All of an organism’s genetic material is called the genome A genotype refers to the actual genes A phenotype is the physical expression of a trait

Genotype The genetic combination of an organism: It consists of 2 alleles: dominant or rececessive For example, if P represents colour of the purple flower: The possibilities are: Pure dominant (homozygous dominant) = 2 dominant genes (PP) Pure recessive (homozygous recessive) = 2 recessive genes (pp) Hybrid (heterozygous) = 1 dominant + 1 recessive gene (Pp)

Phenotype The way an organism looks: No matter what genes are present, phenotype of the dominant gene is always expressed EXCEPT for homozygous recessive (pp)

Gregor Mendel’s observed traits: Recessive traits: traits that “disappear” Rule of Dominance: When a dominant trait is present the recessive trait is hidden Yes, you are special! Atypical traits

How’s it related???? You have 4 minutes and 25 seconds to draw a concept map to show (with words, chart, or a concept map) how these terms are related. Gene Genotype Phenotype Allele Dominant traits Recessive traits Homozygous Heterzygous