In a Pedigree Chart, the genotype for each individual is not show, therefore we must infer what allele pair they have by looking at their parents and offspring and what traits they all carry. Some individuals carry a trait but might not be physical shown- this means they are heterozygous.
In the Pedigree Chart above, the recessive gene of strait hair is possessed in a large number of members in the family, but there are a couple with dominant curly hair. In the first generation, the mother has curly hair, which is exhibited by the filled in circle representing the dominant gene. The father has recessive strait, making his alleles a homozygous recessive pair. We can infer by looking at generation two, that the moth must be heterozygous because the children have the recessive gene of strait hair.
In the Pedigree Chart above, the recessive gene of strait hair is possessed in a large number of members in the family, but there are a couple with dominant curly hair. In the first generation, the mother has curly hair, which is exhibited by the filled in circle representing the dominant gene. The father has recessive strait, making his alleles a homozygous recessive pair. We can infer by looking at generation two, that the moth must be heterozygous because the children have the recessive gene of strait hair.