Final answer:
Mendel's principle of segregation states that an organism's offspring inherit one allele for each gene from each parent, ensuring a combination of one of each allele for every gene.
Step-by-step explanation:
The principle that states that only one of the alleles from each parent gets passed down to the next generation is known as Mendel's principle of segregation. This principle elaborates that for any given trait, each parent contributes one allele to their offspring.
As a result, offspring receive a combination of alleles, one from each parent. During the process of fertilization, sperm and egg cells unite and each contributes their set of alleles, ensuring that the new organism has one allele for every gene from each parent. If an allele is dominant, it will be expressed over a recessive allele, which will only be expressed phenotypically if the organism inherits two recessive alleles.
For example, in pea plants, a heterozygous individual has one dominant and one recessive allele. If a parent is heterozygous for a trait, such as flower color, there is a 50% chance of passing on the dominant allele, and a 50% chance of passing on the recessive allele. When Mendel performed monohybrid crosses, he discovered the 3:1 dominant-recessive ratio in the resulting offspring. This ratio demonstrated the principle of segregation and the concept that each parent passes down only one allele for each trait.