Mendel's Law of Segregation

3. When gametes (sex cells) are produced, allele pairs separate or segregate leaving them with a single allele for each trait. This means that sex cells contain only half the compliment of genes. When gametes join during fertilization the resulting offspring contain two sets of alleles, one allele from each parent. For example, the sex cell for the green pod plant had a single (G) allele and the sex cell for the yellow pod plant had a single (g) allele. After fertilization the resulting F1 plants had two alleles (Gg).

4. When the two alleles of a pair are different, one is dominant and the other is recessive. This means that one trait is expressed or shown, while the other is hidden. For example, the F1 plants (Gg) were all green because the allele for green pod color (G) was dominant over the allele for yellow pod color (g). When the F1 plants were allowed to self-pollinate, 1/4 of the F2 generation plant pods were yellow. This trait had been masked because it is recessive. The alleles for green pod color are (GG) and (Gg). The alleles for yellow pod color are (gg).