Alleles may occur in pairs, or there may be multiple alleles affecting the expression (phenotype) of a particular trait. … If the paired alleles are the same, the organism’s genotype is said to be homozygous for that trait; if they are different, the organism’s genotype is heterozygous.
Do the alleles have to be the same for each trait?
When genes mutate, they can take on multiple forms, with each form differing slightly in the sequence of their base DNA. These gene variants still code for the same trait (i.e. hair color), but they differ in how the trait is expressed (i.e. brown vs blonde hair). Different versions of the same gene are called alleles.
Do alleles affect more than one trait?
The majority of human genes are thought to have more than two normal versions or alleles. Traits controlled by a single gene with more than two alleles are called multiple allele traits. An example is ABO blood type.
Multiple Allele Traits.
|Genotype||Phenotype (blood type)|
What do alleles influence?
Alleles contribute to the organism’s phenotype, which is the outward appearance of the organism. Some alleles are dominant or recessive. When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype.
Where do alleles come from?
One allele for every gene in an organism is inherited from each of that organism’s parents. In some cases, both parents provide the same allele of a given gene, and the offspring is referred to as homozygous (“homo” meaning “same”) for that allele.
How many alleles are in a trait?
Most traits are determined by more than two alleles. Multiple forms of the allele may exist, though only two will attach to the designated gene site during meiosis. Also, some traits are controlled by two or more gene sites. Both possibilities multiply the number of alleles involved.
What are alleles and how do they affect our traits?
Each variation of a gene is called an allele (pronounced ‘AL-eel’). These two copies of the gene contained in your chromosomes influence the way your cells work. The two alleles in a gene pair are inherited, one from each parent. Alleles interact with each other in different ways.
Why it is advantageous to have 2 alleles per trait?
Since genes come in more than one version, an organism can have two of the same alleles of a gene, or two different alleles. This is important because alleles can be dominant, recessive, or codominant to each other.