Making a Pedigree Chart

Quick Review Genotype=what genes someone has Genes are usually represented by a letter, a capital letter for the dominant trait, a small case for the recessive. Ex. Tongue Rolling is dominant, so we use R to represent the tongue rolling Inablilty to roll your tongue is recessive so we use r to represent the non-rolling gene For every trait, you get a gene from each parent

Genotypes and Phenotypes Mom and Dad are Rr-that is their genotype, they can also be described as heterozygous-they have 1 of each gene What is their PHENOTYPE? The youngest son has a genotype of rr-he is Homozygous recessive-2 copies of the recessive gene His phenotype? tongue rollers Rr Rr I can’t Roll my Tongue! Rr rr Rr Rr non-roller

Some common dominant and recessive traits Widow’s peak is dominant. You can be homozygous dominant (WW) or heterozygous (Ww) and you will have widow’s peak What is your genotype and phenotype if you’re homozygous recessive? ww, no widow's peak

Making a Pedigree Chart Pedigree charts are made to chart family history and see how traits are passed What generations are these? P1 F1 F2

Symbols Used-write it down! Shade individuals that have the trait you’re studying Boys=squares (Lucy always calls Charlie Brown a ‘block head’) Girls-circles

Married-connected at side Siblings-connected at TOP not at the side (hopefully not siblings AND married) Oldest child-to the left Question-if shaded individuals in this pedigree have blue eyes, what is the GENOTYPE of the parents? both must be Bb