What does the number of phenotypes depend on?
Having more than 1 or 2 alleles for a trait can greatly increase the number of phenotypes, depending on the trait’s specific pattern of inheritance. For example, human blood type is controlled by 3 alleles (just referring to the ABO blood groups here): A, B, and O.
What determines the number of phenotypes for a given trait *?
The number of phenotypes for a certain trait is usually influenced by the number of genes that control the trait. It can either be a single-gene trait or a polygenic trait. A single-gene trait refers to a characteristic or a phenotype that is controlled by one gene.
How do you determine the number of phenotypes?
The number of different genotypes is 3 n where n = number of genes. For simple dominant–recessive relations, the number of different phenotypes is 2 n , where n = number of genes.
What two testable assumptions were the basis for Darwin’s hypothesis about the evolution of the Galapagos finches?
What two testable assumptions were the basis for Darwin’s hypothesis about the evolution of the Galápagos finches? natural selection, and the variation, such as differences in beak size, must produce differences in fitness.
How does the phenotype depend on its genes?
Genotype versus phenotype. An organism’s genotype is the set of genes that it carries. An organism’s phenotype is all of its observable characteristics — which are influenced both by its genotype and by the environment. … For example, differences in the genotypes can produce different phenotypes.
What does it mean if the 23rd pair of chromosomes reads XY in humans?
The 23rd pair of chromosomes are two special chromosomes, X and Y, that determine our sex. Females have a pair of X chromosomes (46, XX), whereas males have one X and one Y chromosomes (46, XY).
What are the 3 main sources of genetic variation?
For a given population, there are three sources of variation: mutation, recombination, and immigration of genes.
Does each gene of a polygenic trait often has two or more phenotypes?
Each gene of a polygenic trait often has two or more phenotypes . A single polygenic trait often has many possible genotypes . A symmetrical bell-shaped graph is typical of polygenic traits .
How many phenotypic classes are expected?
Polygenic inheritance can be explained by additive effects of many loci: if each “capital” allele contributes one increment to the phenotype. With one locus and additive effects we have three phenotypic classes: AA, Aa and aa.
How many genotypes and phenotypes are possible?
When the gene for one trait exists as only two alleles & the alleles play according to Mendel’s Law of Dominance, there are 3 possible genotypes (combination of alleles) & 2 possible phenotypes (the dominant one or the recessive one).