![recessive vs dominant traits recessive vs dominant traits](https://www.yourgenome.org/sites/default/files/styles/banner/public/banners/facts/what-are-dominant-and-recessive-alleles/dominantrecessive-01.jpg)
When studying people in a family, a pedigree depicting the phenotypes of two to three generations can be used to extrapolate the unknown genotypes. Directions: Check off in the table below whether you inherited the dominant (D) or recessive (R) gene for the following genetic traits.
![recessive vs dominant traits recessive vs dominant traits](https://learn-genetics.b-cdn.net/basics/patterns/images/confusingmisleading.png)
Since homozygous dominant and heterozygous display the same phenotype, 75 percent of the F2 generation will express the dominant – or wild type – trait, and 25 percent will express the recessive trait the ratio is 3:1. If two of those heterozygous individuals are mated, 25 percent of the resulting F2 generation will be homozygous dominant, 50 percent will be heterozygous, and 25 percent will be homozygous recessive the ratio is 1:2:1. In a simple cross between a homozygous dominant parent and a homozygous recessive parent, all the F1 offspring will be heterozygous – each will have one dominant and one recessive copy of the gene – and the phenotype will be the dominant trait. The first generation of offspring is called F1, and the next generation is F2, etc. Punnet squares are graphs representing the genotypes that would hypothetically result from a cross of parents of known genotype. For example, in X-linked recessive traits, males are much more commonly affected than females. Determine if the chart shows an autosomal or sex-linked (usually X-linked) trait. If the trait is dominant, one of the parents must have the trait. On the other hand, a recessive trait only affects an individual if he has two identical – homozygous – copies of that gene. Reading a pedigree Determine whether the trait is dominant or recessive. A dominant trait is expressed (phenotype) whenever that allele is present, whether homozygous or heterozygous (genotype). The combination of genes results in the phenotype, the actual observable trait. Homozygous and heterozygous describe the genotype. An individual is homozygous for a particular gene if he has two identical versions of that gene whereas, he is heterozygous if he has two different versions of that gene. Mendelian traits – the characteristics studied by Gregor Mendel – are determined by a single gene.