Tuesday, April 5, 2011
Bozo family and Haplogroups
The Bozo family example used by Shubin to describe the subtle process of evolution over many generations reminded me of an idea that was introduced during the genetics unit: haplogroups. I believe human haplogroups demonstrate the theme of evolution within the human species because is shows how features, such as blonde hair or black skin, eventually developed as humans migrated out of their origins in Africa and adapted to their environments across the planet. In the words of Shubin, "the key is that features--orange hair, squeaky nose, big floppy feet--enable you to recognize the groups. These features are your evidence for the different groups, or in this case generations, of clowns." (177). My question about haplogroups is how they are distinguished specfically. Obviously features across different populations are diverse, but are specific patterns of features (and genetic patterns) used to group people together? Also, can haplogroups be used to trace the origins of mutations, such as sickle-cell anemia, to explain where evolution did not work well and produced not so good results? I think my Y-DNA may be in haplogroup J due to my Sicilian and Mediterranian ancestory. Are you curious about what haplogroup you are in? Troy Glickstern cleverstar8@comcast.net
Subscribe to:
Post Comments (Atom)
This comment has been removed by the author.
ReplyDeleteI think this is an interesting idea, but you're depending too much on the thought that some of these haplogroups only existed after migration. Like all other features seen in organisms, haplogroups are just a different type of variation. For example, Haplogroup A is a Y-chromosome line originating from the Southern Nile and Africa. However, the M91 line can be found there too, just in smaller amounts. What probably happened with haplogroups is that they were present as a type of variation. The genes may have had a tendency be connected because they were located near each other on chromosome, creating some sort of recombination. (Campbell 292) However, they were still present in these environments or in the genotypes themselves. Because of the environment the humans were in at the time, the haplogroup wasn't seen, but once they had moved into a different area, most likely one that had been better suited to the genes carried by the haplogroup, they began to show up more. http://genome.cshlp.org/content/early/2008/04/02/gr.7172008.abstract. Also, sickle cell anemia is an interesting story. The sickle cell gene is found in areas with the greatest amount of malaria epidemics. This was actually a process of natural selection. Malaria would kill almost anyone within a few weeks at most. Sickle cell anemia however, only killed people in their late twenties. An interesting thing that was found was that the shape sickle cell creates in the cells disallows malaria from being able to infect the body. Therefore, in a time where there were no medicines against malaria, sickle cell was actually a genetic defense. http://sickle.bwh.harvard.edu/malaria_sickle.html
ReplyDelete