What Is The Genotype Ratio

The genotypic ratio shows the number of times a characteristic of an organism volition exist seen in the offspring when genes for certain traits are crossed. This more easily understood by using the Punnett square method and a basic monohybrid cross as shown in Effigy 1.

Punnett square mendel flowers
Figure 1: The image above shows a Punnett square monohybrid cantankerous of male and female pea plants that are both heterozygous dominant for purple. The genotypic ratio for this cross is written 1:ii:one.

In animals and plants, each factor has 2 alleles or variations, ane from each parent. When male and female gametes come up together (cantankerous) all the phenotype variations for the offspring are predicted using the Punnett square filigree. The pairs of alleles for male person and female are plotted individually on a grid. Then, each square in the filigree is filled in with the respective combinations of alleles coming from the parents.

To find the genotypic ratio, count the number of times each combination appears in the filigree, starting in the upper left square. The example in Figure i beneath is crossing alleles for just one trait, blossom color. Larger Punnett squares are used to summate genotypic ratios for more than ane trait equally shown in Figure 2.

Punnett square 3
Figure 2: The image higher up shows a Punnett square for figuring out the genotypic ratio using 4 traits from each parent. Reading the grid starting in the upper left foursquare, the genotypic ratio is 1:2:ii:ane:iv:ane:ii:ii:1.

References

Wilson, D. (2012). Punnett squares. Retrieved from lecture notes online. Website: http://sctritonscience.com/Wilson/biology_punnett_squares.htm

Cite This Article

MLA APA Chicago

Biologydictionary.net Editors. "Genotypic Ratio." Biology Dictionary, Biologydictionary.net, 26 Mar. 2018, https://biologydictionary.net/genotypic-ratio/.

Biologydictionary.net Editors. (2018, March 26). Genotypic Ratio. Retrieved from https://biologydictionary.net/genotypic-ratio/

Biologydictionary.internet Editors. "Genotypic Ratio." Biology Dictionary. Biologydictionary.cyberspace, March 26, 2018. https://biologydictionary.net/genotypic-ratio/.