Polygenic inheritance refers to the concept that a trait or characteristic is determined by the combined effect of multiple genes, rather than a single gene. This means that the expression of a trait is influenced by the interaction of several genetic factors, each of which may have a small effect on the trait.
An example of a trait that is influenced by polygenic inheritance is height. Height is a trait that is influenced by many different genetic factors, each of which may have a small effect on the final height of an individual. In addition to genetics, environmental factors such as nutrition and exercise also play a role in determining an individual's height.
Polygenic inheritance is important because it helps to explain why traits often show a continuous range of variation rather than being limited to a few discrete categories. For example, instead of being either tall or short, an individual's height may fall anywhere along a continuous spectrum.
Another example of a trait that is influenced by polygenic inheritance is skin color. Skin color is determined by the amount and distribution of pigments called melanin in the skin. The production of melanin is influenced by multiple genetic factors, each of which may have a small effect on the final skin color of an individual.
Polygenic inheritance is important for understanding the genetic basis of complex traits, such as height and skin color. By understanding the genetic basis of these traits, scientists can better understand how they are influenced by environmental factors and how they may be influenced by genetic intervention.
In conclusion, polygenic inheritance refers to the concept that a trait or characteristic is determined by the combined effect of multiple genes. This is important for understanding the genetic basis of complex traits and how they are influenced by environmental factors.
Polygene
Polygenic dominance describes a relationship between the alleles of a polygenic trait where some alleles are dominant and others are recessive. Basically, the genotype of an individual sets the range of the quantitative trait while the phenotype of the trait is eventually an outcome of the environmental factors. Learn more about Mendel's law of inheritance here Author information Name: Dean Jakubowski Ret Birthday: 1996-05-10 Address: Apt. Ans: Joseph Gottlieb Koleuter is known as the Father of Polygenic Inheritance. Figure 3: Kernel color — polygenic inheritance in wheat. Genetics of the evolutionary process.
It is also another example whose expression is controlled by 5 genes. Polygenic Inheritance in Humans There are many examples of polygenic inheritance in humans like skin and hair colour, height, eye colour, the risk for diseases and resistance, intelligence, blood pressure, autism, longevity, etc. The variation in the length of the corolla in tobacco is due to polygenic inheritance. But if the F 1The plants are crossed further, so in the F 2In the 1st generation, there would be 1 white heart plant, while 63 red heart plants of various shades would be produced. In humans, for example, height, eye color, and hair color all exhibit persistent distribution that can be shown by a bell-curve graph. A different number of alleles contribute to each colour. Accordingly, under different environmental conditions, the gene function may switch OFF or switch ON.
These are essentially responsible for adaptive changes. The more capital letters there are in the genetic pattern, the darker the skin color and vice versa. Due to this, peoples retain amino acid phenylalanine in the body in high proportion resulting to build to a toxic level in their bodies. Individuals who inherit no dark alleles will have very light skin color and those with dark alleles will have very dark skin color. The expression of one gene is not masked by the presence of the other genes, i.
Principles of polygenic inheritance. The additive impact means every contributive gene produces one unit of color. How Is Eye Color Determined? Is blood type an example of polygenic inheritance? Eye color is also determined by other genes. Polygenic Inheritance of Traits Like Eye Color and Skin Color. The alleles in this control the pigment that controls the skin color, which is called melanin.
Polygenic inheritance: definition, characteristics, examples and influencing factors (2022)
These alleles crossed in the F 1 generation produce intermediated red color have Aa Bb Cc. Complete dominance is where the dominant allele will completely mask the effect of the recessive allele, which then hides the other allele in a heterozygous condition. Furthermore, people have a spectrum of skin tones and eye colors. Some examples of polygenic traits are height, skin color, eye color, and hair color. So, the genotypes BBee , Bbee , and bbee all produce the same yellow phenotype.
If a dark red wheat kernel is crossed with a white wheat kernel, all the F1 offspring obtained have an intermediate red colour kernel, i. If this diet is strictly followed from a very young age, the person will have few or no symptoms of the disorder. Polygenic locus may be either a single or complex genetic locus in the conventional sense, i. Genetics, A conceptual Approach fifth edition. Generally, three or more genes govern the inheritance of polygenic traits.
Humans have nine distinct eye hues. Human Eye Color 1. Around 60 loci contribute to the inheritance of a single trait. The polygenic inheritance pattern is difficult to predict and very complex. Height, weight, hair color, eye color, and skin color are examples of polygenic traits.
At least 9 colours of eye are recognised in humans. However, if two pairs of genes control color and the dominant allele at both loci must be expressed to get red flowers, then crossing two heterozygotes Aa Bb will give you red and white flowers in a ratio of 9:7. So, what is a polygenic trait? Polygenic Inheritance of Skin Colour Using Punnett Square in F2 Generation B. Instead, polygenic traits exhibit incomplete dominance, therefore, the phenotype displayed in offspring could be a mixture of the phenotypes displayed within the parents or grandparents. In this case, a cross between two individuals with light brown eyes BbGg would produce several different phenotype possibilities. Polygenic inheritance and natural selection.
Human height is controlled by multiple genes, and environmental factors such as diet and health can influence human height. What are examples of polygenic traits? National Library of Medicine, National Institutes of Health, May 2015, ghr. The progeny of the parents with genotype AABBCC and aabbcc will have intermediate color in the F1 generation, i. The genes of polygenic inheritance known as polygenes have a minor effect on a phenotype along with the other genes. Unlike Mendelian inheritance, polygenic inheritance does not have any genes called dominant or recessive.
