Genotypes Phenotypes Science 9 Genetics u The Study

Genotypes & Phenotypes Science 9

Genetics u The Study of Genes – Genes are composed of a segment of DNA that encodes a particular protein – Genes pass on genetic traits to offspring – Contain the hereditary info

Alleles u Responsible u One for hereditary variety member of a pair or series of different forms of a gene

Homozygous u. A gene that carries two of the same allele u Can be either dominant or recessive – Homozygous dominant: contains two alleles of the dominant trait u BB – Homozygous recessive: contains two alleles of the recessive trait u bb

Heterozygous u. A gene that contains two different alleles – Bb

Dominant vs Recessive u Dominant: The stronger of the two alleles u Recessive: The weaker of the two alleles u The dominant trait will appear in homozygous dominant and heterozygous u The recessive trait will only appear if the gene is homozygous recessive

Genotypes u The set of genes within the DNA responsible for a particular trait u Referred genes to as the sum of all its

Phenotype u The observable characteristics of an individual u Genotype vs Phenotype: – Genotype is the set of all the genes that an individual carries; the phenotype is what we can see of an individual

Genotype vs Phenotype

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Punnett Squares u Allows you to determine the possible genotypes and phenotypes of offspring u Used to determine the probability of genotypes of offspring

Punnett Squares u Genotypes show the possible genetic make-up of the offspring – AA/Aa/aa u Phenotypes say the traits that the genotypes express – Blue eyes/brown eyes

Example

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