What determines a trait of an organism
the number of dominant alleles
its phenotype
the combination of its alleles
the number of copies of the gene
All of the factors mentioned contribute to determining a trait of an organism. However, to provide a more complete answer, it is essential to mention that the trait of an organism is primarily determined by the combination of its alleles, which are the alternative forms of a gene. A gene is a segment of DNA that carries the information for producing a specific protein or RNA molecule, and these molecules are responsible for various traits in organisms.
Within a population, an individual can have different combinations of alleles for a specific gene. These alleles can be dominant or recessive, where dominant alleles mask the effect of recessive alleles. The particular combination of alleles an organism possesses ultimately determines its genotype, which refers to the actual genetic makeup of the organism.
The phenotype, on the other hand, is the observable physical or biochemical characteristic resulting from the interaction between the organism's genotype and its environment. The phenotype includes traits like eye color, height, and blood type, among others. While the genotype sets the potential range of phenotypic possibilities, the actual expression of a trait depends on multiple factors, including the interaction between the alleles themselves and their interaction with environmental factors.
Additionally, the number of copies of a particular gene can influence the expression of a trait. For example, in some cases, a gene may have multiple copies, known as gene duplication. These extra copies can enhance the expression of the trait or provide redundancy and serve as backups if one copy becomes defective.
In summary, the trait of an organism is primarily determined by the combination of alleles it possesses, which forms its genotype. However, the phenotype, or the observable trait, is the result of the complex interaction between the genotype and the environment. The number of dominant alleles, the phenotype, the combination of alleles, and the number of gene copies all play roles in determining the trait of an organism.