Dihybrid Punnett Squares This tests for two traits! Lets cross RRYY with rryy List the phenotypes of the offspring RY RY RY RY RrYy ry ry ry ry

Dihybrid Cross RY Ry rY ry RY Ry rY ry Try crossing two heterozygous parents: RrYy & RrYy List the genotypes, phenotypes & probability of the offspring: RY Ry rY ry RRYY RRYy RrYY RrYy RRyy Rryy rrYY rrYy rryy RY Ry rY ry

Incomplete Dominance If you cross a red four o’clock flower with a white four o’clock flower which one will be the dominant color? Neither! The flowers will be pink! When neither allele is completely dominant over another this is called incomplete dominance

Incomplete Dominance Cross Red four o’clocks are RR White four o’clocks are R’R’ All offspring are pink!! R R R’ R’

The second (F2) generation! Now cross two pink offspring! What do the offspring look like? (1 red, 1 white, 2 pink) R R’ R R’

Co-dominance This is when both alleles express themselves in the offspring equally Red horse (R ) crosses with a white horse (W) All offspring will be roan (every other hair is white) R R W W