2What do Bart, Lisa & Maggie all have in common? Why?
3Traits can be… DOMINANT recessive More likely to be seen Dominant overpowers the recessive traits.recessiveLess likely to be seenCan sometimes be“hidden” within your genes.or
4Most of these characters are the same species. But how are they different?
5We inherit our traits from our parents Allelesevery trait is decided by two alleles (one from Mom, and one from Dad)They can be dominant or recessiveWe get 23 chromosomes from Mom and 23 from Dad.This equals 46 chromosomes.Genes – the instructions for traitsWe represent these alleles with letters.Brown hair- dominant allele - BBlond hair- recessive allele - b
7Phenotype The appearance of the organism. PHENO is like PHOTO What you would be able to see in a photo?spotted coat, short hair, long hair, floppy ears short earsbrown hair, curly hair, brown eyes, freckles, dimples, face shape
8Genotype The genetic makeup of an organism. This is not visible, but inside their genes (DNA).Tongue rolling – dominant allele – TNot able to roll tongue- recessive - tCan roll tongue – TT, TtCannot roll tongue - tt
9PUNNETT SQUARES First, make a box with 4 squares inside it Second, put both parents Alleles in the right spot.Mom, Rr, can roll tongueDad, rr, can’t roll tongueR rr
10PUNNETT SQUARES Rr rr rr Rr Bring down each letter Bring over each letterThis will make 4 possible combinationsR rrRrrrrrRr
11PUNNETT SQUARES Rr rr rr Rr What are the possible Genotypes? What are the possible phenotypes?Give a ratio for eachR rrRrrrrrRr