Artificial Selection

Artificial Selection; It comes in ways some of us could never think of. Artificial selection is the selective breeding carried out by humans to alter a population. It is a procedure often used in agriculture: artificial selection has been used to alter the number of eggs laid by hens, the meat properties of bullocks, and the milk yield of cows. It has resulted in plants that are more disease-resistant, cows that produce more milk, and racehorses that run faster.

Altering the gene pools of dogs is another more popular technique used in artificial selection, it allows us to choose a dog's hair colour, length, ear length, bone structure, muscle mass, and more! The possibilities are endless:

(top row- Alaskan Malamute, Basset Hound, Llasa Apsa;

Middle row- Beagle puppy, Shar Pei, Chow)

There is a fault within the artificial selection process; if we continue to select a certain gene in dogs for example, within time, the variation between dogs would be obsolete. No more german sheppards or golden retrievers... just pugs. So if we do happen to end up with just pugs or any one kind of dog, the bottleneck effect could occur. This is when an event in which a population’s size is greatly reduced. When this happens, genetic drift may have a substantial effect on the population. In other words, when the population size is radically reduced, gene frequencies in the population are likely to change just by random chance and many genes may be lost from the population, reducing the population’s genetic variation. All in all, a disease could appear for these pugs, and one of them could inherit the disease, causing the rest of the generations to suffer and possibly become extinct.

I always knew pugs were trouble...

Artificial selection gets deeper and more complex as we proceed. Chickens are beings artificially produced so that they grow faster and bigger than regular chickens. They are also being altered so that they are featherless which makes it easier for corporations to work faster in producing food and getting it to the consumer faster. Although the job is done faster, a featherless chicken is more prone to diseases and viruses.

Altered, featherless,fast growing, stronger, more egg-producing CHICKEN.

Artificial Selection is good in a lot of aspects! Choosing the genes which are least likely to lead to easy entry of viruses can be good for most habitats and species. Artificial selection in plants can eventually and hopefully lead to pharmaceutical and medical discoveries. Experiments have resulted in allowing us to speed up the growth of animals and plants, even changing their colours!

Belgian Blue cow. The defect in the breed's myostatin gene is maintained through linebreeding

and is responsible for its accelerated lean muscle growth

Researchers at the USDA have selectively bred carrots with a variety of colors.

Here is a video on the general idea of artificial selection through time:

That is all for today! In conclusion, I think it should be ethically alright to tamper with selection in animals and plants, but if it keeps viruses, diseases, and other bad traits away then it should be a plus for the world.

-Girgis

Bibliography:

http://www.youtube.com/
en.wikipedia.org/wiki/Artificial_selection
library.thinkquest.org/C0118084/.../artificialselection.htm
www.blackwellpublishing.com/ridley/.../Artificial_selection.asp

Blogs Commented On:

RJ Aparato (comments don't work... this is my post)

http://rjsbioblog.blogspot.com/

Hey RJ, those belgium cows are really, REALLY big! You know even though they are genetically altered to have more meat, most people consider more meat a bad thing. But the meat in these "belgium blues" actually contains less cholesterol and calories. Another point is that when you said us humans usually eat just cows,pigs,lamb, or chicken I thought it was a really good point! It's kind of true, well in my area at least. In other areas of the world like Asia or Africa this might not be the issue, but in Canada and America, it applies very well. So what is the problem with altering our sources of food in order to create a healthier and good environment that meets our daily needs? Well that's basically it, good job on the blog.

Timothy Vasquez

http://bioblogtvasq.blogspot.com/