Question

Compare Figure 13.12 with Figure 24.18. What cellular process could cause the hybrid chromosomes in Figure 24.18 to contain DNA from both parent species? Explain.

Short answer

In figure 24.18, sunflower species H. annuus is crossed with H. petilolarus, which produced a hybrid species. The cellular process that occurs in these two species when compared with figure 13.12 (Meiosis I) is recombination.

The hybrid species are formed from the crossing over or recombination of chromosomes during fertilization.

Step-by-step solution

Recombination

The phenomenon that occurs during the fertilization of gametes is called recombination. Each gamete contains haploid chromosomes of parents. These homologous chromosomes from each parent recombine randomly, resulting in the formation of a new individual.

Hybrids

A species with a mixed origin of two subspecies is called hybrid. Examples of hybrid animals are mule and liger. Most of the hybrid animals show less fertility. Examples of hybrid plants are kiwifruit, brinjal, great-headed garlic, and coconut breeds.

Hybridization

Humans play a significant role in speciation. For the production of desired traits in plants or animals, artificially selected traits are combined in a laboratory through a hybridization technique. For example, the crossing of two sub plant species gives rise to hybrid plants.

The DNA of a hybrid organism contains chromosomes of both the parents, and some of the traits of both plants appear in the organism's phenotype. The recombination of chromosomes during fertilization allows this process.