Exploring Human Genetic Diversity through Haplotype Data

The Big Question

 

• What does genetic variation tell us about the Human Race(s)?

• Open in a new window the  Haplogroup World Map  to see the latest data on genetic variation of human populations across the planet.
  

 

 

 

 

Background information on Population Genetics of Homo sapien 

 

• Haplotype is a haploid genotype at a set of genetic loci on either the Y Chromosome or mtDNA.

 

• Haplogroup is variously defined, but originally described as a group of haplotypes delineated by a conserved common Single Nucleotide Polymorphism (SNP) - for mtDNA - or a discrete, non-overlapping suite of haplotypes - for the Y Chromosome.  Haplogroups can be farther subdivided by other less common SNP's or additional conserved assemblages of haplotypes.

 

  from http://www.cstl.nist.gov/biotech/strbase/images/Y%20STR%20Positions.jpg

 

"At some Y-chromosome locations, there are small segments of base pairs that are repeated in the DNA. Markers with these types of repetitions are called "STR markers," where STR means "Short Tandem Repeat."

For instance, a particular genetic sequence at marker location DYS391 might be:

TGTCTG/TCTA/TCTA/TCTA/TCTA/TCTA/TCTA/TCTA/TCTA/TCTA/TCTA/TCTGCCT

Note there are ten repeats of the segment TCTA. The number of repeats is the "value" or haploid genotype (haplotype) at that marker.

In this example, the haplotype at DYS391=10."

From: SMGF.com

 

 

 

 

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Haplogroup I is defined by the following mutations in HVR1 of the d-loop:

 

 

 

 

Regions of Diversity suggest a point of Origin.

 

 

 

• Evidence for a Molecular Clock
• Biogeography of North American Quail
• Ape Diversity Biogeography

 

Regions of Ancestral as opposed to Derived traits also suggest a point of Origin.

 

• Example of rooted versus unrooted trees

 

 

 

 

 

Related Links:

• More details on Y STR's

• Example of I Haplogroup

 

• mtDNA Haplogroup tree   (MITOMAP: A Human Mitochondrial Genome Database. http://www.mitomap.org, 2008.)

 

• Definitions from SMGF.com

• Journey of Mankind (Early Migration of Homo sapien)

 

 

Assignment:

Look over the Global Haplotgroup Map and answer the following questions (post in your assignment blog with the Post-Lab from the Gel Electrophoresis assignment).

1. Is there a single haplogroup that can be used to define an individual?
2. Is there a single haplogroup that can be used to define a population? 
3. Can a set of Haplogroups define a populations?
4. Is it always the case that there is more similarity in individuals within populations versus between populations? Give examples to support your claim.
5. Explain the observed haplogroup global pattern?  Describe your hypothesis in as much detail as possible. 
6. How does the last two lab activities (genotyping the PV92 marker) connect to the idea of genetic variation and hence, the concept of race in humans.
7. Give your final account of how biology informs us about race.