Final answer:
The shepherd's purse plant demonstrates gene redundancy through dominant epistasis. Both Harebell and Snapdragon plants exhibit this trait, where a dominant allele at one gene locus overshadows the other, leading to a 15:1 phenotypic ratio in crosses between heterozygous plants.
Step-by-step explanation:
The shepherd's purse plant (Capsella bursa-pastoris) shows gene redundancy due to dominant epistasis, which is a form of gene interaction where the presence of a dominant allele at one locus masks the effects of alleles at another locus, leading to a 15:1 phenotypic ratio in the offspring from a cross between heterozygotes for both genes. This means that plants 3) Both Harebell and Snapdragon plants have gene redundancy. When considering a cross between two heterozygous plants (AaBb x AaBb), we can expect the majority of the offspring to display the characteristic of triangular seed shape, with a small proportion (1 out of 16) of the seeds being ovoid.
In answering the question, we refer to the dominant epistasis that occurs within the shepherd's purse plant. In this scenario, each plant can possess alleles A or a, and B or b. Due to the epistatic relationship, if either gene A or B is present in the dominant form (A- or B-), the seeds will be triangular. The only way to get ovoid seeds is if both genes are homozygous recessive (aabb). This distinct genetic relationship is indicative of gene redundancy since the presence of a dominant allele in either gene will express the same phenotype, thus creating a redundant effect.