The trait represented by the coloured circles and squares below is inherited as a dominant allele. This is not a sex-linked trait. Shaded individuals represent the dominant trait. What is the probable genotype of shaded individuals?
All shaded individual are heterozygote
For a dominant trait if any of the two parents is homozygote all the offspring will show the trait in the phenotype. But in the given pedigree individual 5 is showing the recessive phenotype so, 1 and 2 are definitely heterozygote. Same explanation holds good for individual 4.
For individual 8- in a cross between heterozygote dominant and homozygote recessive the offspring showing dominant phenotype will be heterozygote genetically.