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A postzygotic mutation (or post-zygotic mutation) is a change in an organism's genome that is acquired during its lifespan, instead of being inherited from its parent(s) through fusion of two haploid gametes. Mutations that occur after the zygote has formed can be caused by a variety of sources that fall under two classes: spontaneous mutations ...
It is considered postzygotic response because outbreeding depression is noted usually in the performance of the progeny. [3] Outbreeding depression manifests in two ways: Generating intermediate genotypes that are less fit than either parental form.
[3]: 354 [4] [5] Differences in behavior or biology that inhibit formation of hybrid zygotes are termed prezygotic isolation. Reinforcement can be shown to be occurring (or to have occurred in the past) by measuring the strength of prezygotic isolation in a sympatric population in comparison to an allopatric population of the same species.
Reinforcement, under his definition, included prezygotic divergence and complete post-zygotic isolation. [18] Servedio and Noor include any detected increase in prezygotic isolation as reinforcement, as long as it is a response to selection against mating between two different species. [ 4 ]
Behavioral epigenetics is the field of study examining the role of epigenetics in shaping animal and human behavior. [1] It seeks to explain how nurture shapes nature, [2] where nature refers to biological heredity [3] and nurture refers to virtually everything that occurs during the life-span (e.g., social-experience, diet and nutrition, and exposure to toxins). [4]
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation.They prevent members of different species from producing offspring, or ensure that any offspring are sterile.
Reproductive isolation between a hybrid species and its parental species can arise from a variety of reproductive barriers either before or after fertilization (prezygotic or postzygotic, respectively), which may themselves be dependent or independent of environmental conditions (extrinsic or intrinsic barriers, respectively). [77]
When two populations diverge from a common ancestor and become isolated from each other, thus meaning there is no interbreeding between the two, mutations can accumulate in both populations. These changes represent evolutionary change in the populations.