How many genes determine a phenotype?

How many genes determine a phenotype?

Polygenic traits are quite different from the classical Mendelian trait in where we see that one gene controls one characteristic or one phenotype. Surprisingly, most traits in humans, and in fact most traits in most organisms, are polygenic.

How many alleles does a single gene trait have?

two alleles
Genes come in different varieties, called alleles. Somatic cells contain two alleles for every gene, with one allele provided by each parent of an organism.

What is a single gene trait?

Single gene disorders are caused by DNA changes in one particular gene, and often have predictable inheritance patterns. Over 10,000 human disorders are caused by a change, known as a mutation?, in a single gene?. These are known as single gene disorders.

What phenotypes are controlled by one gene?

Most traits are determined by more than one gene. For example, skin color and height are determined by many genes. Some phenotypes however, are determined by a single gene….

• Interlocking fingers. Interlock fingers.
• Ear lobes.
• Widow’s peak.
• Tongue curling.
• Hitch hiker’s thumb.
• Pigmented iris.
• PTC tasting.

Would a trait that has only 2 distinct phenotypes more likely be a single gene trait or a polygenic trait?

A trait with two distinct phenotypes likely would be a single-gene trait. Because each gene of a polygenic trait often has two or more alleles, a polygenic trait can have many possible genotypes and phenotypes.

How are phenotypes determined?

An organism’s phenotype is determined by its genotype, which is the set of genes the organism carries, as well as by environmental influences upon these genes. Phenotypes also include observable characteristics that can be measured in the laboratory, such as levels of hormones or blood cells.

How does the number of phenotypes differ between single gene traits and polygenic traits?

How does the range of phenotypes differ between single-gene traits and polygenic traits? Single-gene traits have only two distinct phenotypes. Polygenic traits can have many possible phenotypes. It can lead to changes in allele frequencies and the evolution of traits.

Is each trait controlled by one gene?

Most traits are determined by more than one gene. For example, skin color and height are determined by many genes. Some phenotypes however, are determined by a single gene. If you exhibit the dominant phenotype, use a dash to represent the second allele.

What traits are determined by more than one gene?

Most traits are determined by more than one gene. For example, skin color and height are determined by many genes. Some phenotypes however, are determined by a single gene. We will explore some of these single gene traits in the laboratory. Use a lab partner to help you determine your phenotype for the traits listed.

How many genes are there in human DNA?

There are thought to be about 20,000 genes in human DNA. Interestingly, the number of genes in human DNA is not appreciably different from the number of genes in chimpanzees or mice. Most traits are determined by more than one gene. For example, skin color and height are determined by many genes.

Are freckles a single-gene trait?

Freckles and no Freckles are single-gene traits. Someone can either have a widows peak or not; making it a single-gene trait. This is the kind of chart you would see for a Single-gene trait.

What is the genotype for the right thumb on top?

The right thumb on top is determined by the ii genotype. The dominant allele (E) results in the phenotype of free earlobes. The recessive allele (e) is for attached earlobes. Widow’s peak occurs when the hairline forms a distinct point in the center of the forehead. Widow’s peak is controlled by a dominant allele (W).