Which of the following is NOT one of Mendel’s major conclusions?

One of Mendel's major conclusions is that organisms inherit two alleles for each trait, one from each parent, which can be either dominant or recessive. The idea that each organism is born with four alleles is incorrect because, in Mendelian genetics, an organism typically has two alleles for each gene (one from each parent) rather than four.

Mendel established that alleles, the different forms of a gene, can exhibit dominance, meaning that one allele can mask the presence of another (the recessive allele) in the phenotype. This is a fundamental concept in genetics that illustrates the relationship between dominant and recessive traits.

The principle of gametes carrying only one allele for each trait is also crucial, as Mendel discovered that during gamete formation, the alleles segregate so that each gamete receives only one allele. This forms the basis for the law of segregation.

Additionally, Mendel's work highlighted that variation in traits is primarily due to the different alleles present in a population. This understanding laid the groundwork for the study of heredity and variation, which are key concepts in genetics.