Polygenic Inheritance Key Takeaways
- In polygenic inheritance, traits are determined by multiple genes, or polygenes.
- Polygenic traits may express several different phenotypes, or displayed characteristics.
- Polygenic inheritance is a type of incomplete dominance inheritance, where the expressed phenotypes are a mixture of inherited traits.
Full Answer
What is different between a multiple trait and a polygenic?
What are the Similarities Between Multifactorial and Polygenic Traits?
- Multifactorial traits are polygenic traits that are strongly influenced by the environment.
- They are controlled by many genes/alleles.
- They are exceptions of Mendelian inheritance.
- Many human disorders are multifactorial or polygenic diseases.
- Multifactorial and polygenic diseases are very complex to resolve.
How many genes influence a polygenetic trait?
Traits controlled by two or more genes are said to be polygenic traits. Many human traits such as height, skin color, hair color, etc. are results of polygenic traits. The image below shows the varying scale of human skin color. Scientists believe that at least three different genes code for skin color. The allele for dark skin, D, is dominant over the allele for light skin, d.
Why are polygenic traits more influenced by the environment?
The phenotype is a mixture of the phenotypes inherited from the parent alleles. Environmental factors can also influence polygenic traits. Polygenic traits tend to have a bell-shaped distribution in a population. Most individuals inherit various combinations of dominant and recessive alleles. These individuals fall in the middle range of the curve, which represents the average range for a particular trait.
Are polygenic traits controlled by no more than three alleles?
Polygenic inheritance defines as more than two alleles (maybe a group of alleles) which control a single characteristic. A single trait that controlled by multiple genes or alleles, is said to be a polygenic inheritance.
How are polygenic traits determined?
In polygenic inheritance, traits are determined by multiple genes, or polygenes. Polygenic traits may express several different phenotypes, or displayed characteristics. Polygenic inheritance is a type of incomplete dominance inheritance, where the expressed phenotypes are a mixture of inherited traits.
How would you recognize the expression of polygenic inheritance?
Polygenic inheritance of the human eye color. The eye color follows a polygenic inheritance pattern. In humans, 9 eye colors are recognized. Phenotypic expression of eye color is controlled by two major genes and 14 additional genes, which are linked to X chromosomes.
What are other factors that can determine the expression of polygenic traits?
Polygenetic traits can result from several different alleles or from multiple genes. The type of alleles and the kind of dominance influences gene expression and the resulting polygenic traits.
What determines how a trait is expressed?
Key Takeaways: Traits Traits are inherited characteristics from our parents that are expressed externally in our phenotype. For any given trait, one gene variation (allele) is received from the father and one from the mother. The expression of these alleles determines the phenotype, whether dominant or recessive.
Which outcome could help you identify a trait whose expression is determined by the effects of two or more genes polygenic inheritance )?
Which outcome could help you identify a trait whose expression is determined by the effects of two or more genes (polygenic inheritance)? The trait varies along a continuum in the population.
What is polygenic trait?
A polygenic trait is a characteristic, such as height or skin color, that is influenced by two or more genes. Because multiple genes are involved, polygenic traits do not follow the patterns of Mendelian inheritance. Many polygenic traits are also influenced by the environment and are called multifactorial.
What kinds of environmental factors influence the expression of traits?
Environmental factors such as diet, temperature, oxygen levels, humidity, light cycles, and the presence of mutagens can all impact which of an animal's genes are expressed, which ultimately affects the animal's phenotype.
Which statement best describes a polygenic trait?
question. The best definition which describes polygenic traits is : B) traits that are controlled by multiple genes. Polygenic traits basically mean the traits that are a result of multiple intertwined traits like for example skin colour.
What are polygenic traits quizlet?
a trait that is controlled by several pairs of genes; different combinations of all the genes contribute to the trait in varying degrees.
What determines the traits of an organism?
Genes are found on chromosomes and are made of DNA. Different genes determine the different characteristics, or traits, of an organism. In the simplest terms (which are actually too simple in many cases), one gene might determine the color of a bird's feathers, while another gene would determine the shape of its beak.
What factors regulate gene expression?
Specifically, gene expression is controlled on two levels. First, transcription is controlled by limiting the amount of mRNA that is produced from a particular gene. The second level of control is through post-transcriptional events that regulate the translation of mRNA into proteins.
What are examples of polygenic traits?
Two example of polygenic traits and height and skin color. Each are controlled by multiple genes, each with multiple alleles and produce a wide co...
What is meant by polygenic inheritance?
Polygenic inheritance occurs when more than one gene, and thus multiple alleles, control expression of a trait. Polygenic inheritance produces tra...
What are characteristics of polygenic traits?
Some characteristics of polygenetic traits are that they are quantitative and appear on a spectrum, such as height. They are also multifactorial a...
What is a polygenic pattern?
A polygenic pattern is a type of inheritance pattern where one trait is controlled by multiple genes. Each gene has multiple alleles and creates a...
What is polygenic traits?
Polygenic Traits Definition. Polygenic traits are traits that are controlled by multiple genes instead of just one. The genes that control them may be located near each other or even on separate chromosomes. Because multiple genes are involved, polygenic traits do not follow Mendel’s pattern of inheritance. Instead of being measured discretely, ...
Why are polygenic traits not inherited?
Because multiple genes are involved, polygenic traits do not follow Mendel’s pattern of inheritance. Instead of being measured discretely, they are often represented as a range of continuous variation. Some examples of polygenic traits are height, skin color, eye color, and hair color.
What are the two traits that are represented by only one gene?
This is because each trait was represented by only one gene which had two alleles: dominant and recessive. If a plant had two dominant alleles, or one dominant and one recessive allele, the flowers were purple, while if it had two recessive alleles, the flowers were white. Polygenic traits also have dominant and recessive alleles, ...
What is the basic unit of heredity?
Gene – The basic unit of heredity; made up of DNA, it is transferred by parent to offspring and codes for a specific part of the offspring’s phenotype. Allele – A certain variant of a gene . Melanin – A pigment in skin, hair, and eyes that affects its color. Phenotype – Any part of an organism’s physical appearance.
How many genes are involved in height?
Height. Human height is controlled by many genes; in fact, there are over 400 genes related to height, and all of these genes interact to make up a person’s phenotype. This is a very large number, but it makes sense because height is a compilation of the lengths of many different body parts, such as leg bones, the torso, and even the neck. ...
Why do people have green eyes?
Green eyes are caused by multiple factors; they are the result of a light brown iris combined with a blue tone given by light scattering.
How does the eye color of a person determine the color of their eyes?
A person’s eye color is determined by the pigmentation of their irises, but also by the way the cells in their irises scatter light.
What is the distribution of polygenic traits?
Polygenic Traits Distribution. Polygenic traits tend to result in a distribution that resembles a bell-shaped curve, with few at the extremes and most in the middle. In polygenic inheritance, the genes contributing to a trait have equal influence and the alleles for the gene have an additive effect.
What are some examples of polygenic traits?
Examples of polygenic traits include skin color, eye color, hair color, body shape, height, and weight.
What is polygenic inheritance?
Polygenic traits may express several different phenotypes, or displayed characteristics. Polygenic inheritance is a type of incomplete dominance inheritance, where the expressed phenotypes are a mixture of inherited traits.
What is polygenic distribution?
Polygenic traits tend to have a bell-shaped distribution in a population. Most individuals inherit various combinations of dominant and recessive alleles. These individuals fall in the middle range of the curve, which represents the average range for a particular trait.
What color does a dominant allele produce?
Having all dominant alleles results in black eye color. The presence of at least two dominant alleles produces the black or brown color. The presence of one dominant allele produces the green color, while having no dominant alleles results in blue eye color.
How many genes are involved in skin color?
This trait is determined by at least three genes and other genes are also thought to influence skin color. Skin color is determined by the amount of the dark color pigment melanin in the skin. The genes that determine skin color have two alleles each and are found on different chromosomes .
What color is dominant in gene 1?
In this example, the allele for black color (B) is dominant to the recessive blue color (b) for gene 1. For gene 2, the dark hue (G) is dominant and produces a green color. The lighter hue (g) is recessive and produces a light color. This cross would result in five basic phenotypes and nine genotypes .
What is a Polygenic Trait?
A polygenic trait is a trait in which the phenotype is controlled by more than one gene. Phenotype is the physical or behavioral traits of an organism, whereas their genotype is the genetic makeup and specific combination of genes and alleles present. Polygenic characteristics are both:
Genetic Inheritance
Genetic inheritance is the way that people inherit their traits. All diploid organisms inherit two sets of chromosomes, one set from the maternal parent and one set from the paternal parent. In humans, each person gets 23 chromosomes from their mom and 23 chromosomes from their dad.
Monogenic Traits and Mendelian Inheritance
Monogenetic traits are traits that are controlled by a single gene. These genes are typically inherited with two alleles, one which is dominant and masks the other, called the recessive allele. This type of inheritance pattern is called Mendelian Inheritance after the Austrian monk Gregor Mendel.
Answer
Polygenic traits are quantitative because their phenotype expression depends on several different alleles found on different chromosomes.
Answer
If there are more alleles present for darker skin tone, then the offspring will have darker skin pigment than the parents may have.
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