Blog Post Module 6: Reflection Prompt
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Inbreeding
Inbreeding is a common phenomenon in natural populations. This
phenomenon occurs when two closely related organisms mate with each other,
producing offspring. Inbreeding can change the distribution of genetic
variation among the populations of plants and animals. Though we have information
on how inbreeding can affect evolution and can identify the costs and benefits
in the populations of plants and animals, we still don’t know everything about
the forces shaping the evolution of nonrandom mating in general.
Inbreeding can lead to the evolution of assertive mating. Assortative
mating is simply a mating pattern where similar phenotypes are mated with
another more often than what is generally expected with random mating. With
inbreeding within a population, we would see an increase in the ability for the
parent to potentially pass on favored traits to their offspring and therefore
we eventually will see a fixing of those favored or desired traits. We would
also see an increase in uniformity to a species. In terms of evolution,
inbreeding could increase the rate of evolutionary change. It can also increase
the rate that natural selection can eliminate unfavorable deleterious alleles
from a population. On top of all this, we could expect to see a higher fitness
that can theoretically allow the organism to survive and mate with more success
than other organisms.
Some costs of inbreeding can be seen in natural populations
of animals and plants as well as humans. With inbreeding, we can see an
increase in undesirable genes and a reduction in the diversity of the genes. An
example of inbreeding in Europe that is well-known concerns, royal families. It’s
been a centuries-long practice to marry within the royal family in Europe. The many
marriages between first cousins led to a high rate of hemophilia among the
members of the family. Another example would be the many, many health issues
King Charles II of Spain. In animals, we see evidence of inbreeding in feral
sheep on a small island off the coast of Scotland. Inbreeding can cause lower
fertility rates and lower “vigor” in organisms. We can see fewer offspring and
higher offspring mortality. Overall, inbreeding can cause birth defects, both
physical and non-physical defects.
Hi Kaitlyn!
ReplyDeleteI also took this weeks blog post in the same direction! Oddly enough, I had sort of eagerly been awaiting it! One concept that I had not touched on in my own post was the idea of increased fitness. It was so interesting how you interjected the idea that inbreeding could actually eliminate unfavorable deleterious alleles from a population (who knew!?). Overall, you did an excellent job with explaining the pros and cons of inbreeding! One idea I'll leave you with is inbreeding among certain species for generations; such as lions, cheetahs, etc. and how they continue to be successful and dodge certain complications of inbreeding? Awesome read!
Hey Kaitlyn! I like that you pointed out how we are still not sure of the forces behind the evolution of non-random mating. Do you think the forces might be similar to the general evolutionary forces such as genetic drift, selection, etc.?
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