Ten unrelated melanistic jaguars were either homozygous or heterozygous for this allele. OI caused by homozygous or compound heterozygous mutations in the WNT1 gene on chromosome 12q13. Flowers of heterozygous plants have a phenotype somewhere between the two homozygous genotypes. Zygosity can either be heterozygous or homozygous. Mice in both the homozygous and heterozygous states develop the seizure phenotype and ataxia. One affected family has been identified with individuals both homozygous and heterozygous for MEN1 mutations. Autosomal recessive disorders occur in individuals who are homozygous for a particular recessive gene mutation. In its simplest form, a pair of alleles can be either homozygous or heterozygous. Pp (heterozygous), and pp (homozygous recessive). Neither individuals with the homozygous or heterozygous form should take iron supplements. Individuals that show the recessive phenotype are known to have a homozygous recessive genotype. The study found that western lowland gorillas are more likely to be heterozygous than homozygous. However, one needs to distinguish between heterozygous and homozygous KOs. These lineages are unable to reproduce sexually due to being homozygous for a recessive allele. He was unable to produce any mice that were homozygous for the yellow agouti allele.