Genetics of Speciation

Speciation is the process by which populations evolve reproductive isolation and become distinct species. It happens when populations build up genetic differences over time.

Genetic changes can affect traits like body features, behavior, or the timing of reproduction. Over time, these differences can build barriers that reduce interbreeding.

For example, changes in a major pigment gene can shift flower color—and that can change which animals visit the flowers.

If different pollinators prefer different colors, then plants with different flower colors get fewer chances to cross, so gene flow drops.

Some Petunia species attract bees, others attract hummingbirds, and others attract hawkmoths—often linked to color, scent, and nectar traits.

Another genetic barrier, especially in plants, is polyploidy, where an organism has extra sets of chromosomes.

For example, the interbreeding—or hybridization—of different species of Tragopogon plants led to the formation of new Tragopogon species. Because these hybrids have more than two sets of homologous chromosomes, they can’t reproduce with either parent species, even though they are fertile.

In some animals, interactions between the host genome and it