GIVEN:
Dominant traits (indicated by capital letters):
Straight hair = S
Smooth chin = C
Recessive traits (indicated by small letters):
Curly hair = s
Rough chin = c
Let us say the male has straight hair and a rough chin (Sscc) while the female has straight hair and a smooth chin (SSCc).
> The male carries a heterozygous genotype for straight hair (Ss) and a homozygous recessive genotype for a rough chin (cc).
> The female carries a homozygous dominant genotype for straight hair (SS) and a heterozygous genotype for a smooth chin (Cc).
Let us cross the male and female using a Punnett square.
Sscc will be Sc, Sc, sc, and sc.
SSCc will be SC, Sc, SC, and Sc.
The offspring will have the following possible genotypes: SSCc (straight hair and a smooth chin), SsCc (straight and a smooth chin), SScc (straight hair and a rough chin), and Sscc (straight hair and a rough chin).
The offspring will have the following possible genotypes: SSCc and SsCc.
A cross between Sscc and sscc will have following offspring genotypes: Sscc and sscc.
A cross between SSCc and sscc will have following offspring genotype: SsCc.
A cross between Sscc and ssCC will have following offspring genotypes: SsCc and ssCc.
A cross between sscc and SsCc will have following offspring genotypes: SsCc, sscc, and Sscc.
I will use a square to indicate male and a circle to indicate female for the pedigree diagram.