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DSST Anthropology as a Discipline

For example if a family with ten children all of whom

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for example, if a family with ten children--all of whom exhibit a particular rare, but neutral, trait--moved to a tiny country hamlet. If all members of the family remained in the hamlet, married, and produced children who also stayed there and produced more children, and if the hamlet remained isolated from the outside world, the trait might become relatively common among residents of the area in a few generations. The near absence of Blood Type B in the American Indian has been attributed to genetic drift . However, B-type blood reaches its highest frequency in some Mongoloid groups thought to be ancestral to the early inhabitants of the New World. An allele is an alternate form of a gene at a given locus (location on a chromosome). Alternate forms of a gene are known as alleles. For example, given the gene for eye color, blue eyes, hazel eyes, and brown eyes are some of the alleles for that gene. A chromosome is an X-shaped collection of genes, and a locus is a specific position on that chromosome. Certain genes are always found on a certain chromosome (Humans have 23 pairs of chromosomes) at a certain locus. Another example of alleles--the gene for ABO blood group has three alleles, A, B, and O. Allele Frequency is the commonness of a particular allele in a given population, stated as a number, from 0 to 1, or as a percentage, from 0 to 100. Genotypic Variations are caused by differences in number or structure of chromosomes or by differences in the genes carried by the chromosomes. Eye color, body form, and disease resistance are genotypic variations. As you recall, a person's genotype is the set of genes they carry. Typically differences in genotype are simply because one person has a unique set of alleles for his various traits given to him by his parents. Other possible differences, which are out of the ordinary, are having a different number or structure of chromosomes (instead of the ordinary 23 pairs of chromosomes). Genetic variation causes people to have different natural hair colors or different blood groups, but this is not to say that a particular hair color or blood group is 'better' than another. In the case of genetic mutations that cause diseases such as cystic fibrosis or Huntington's disease, it might be reasonable to say that these mutations are deleterious. With most forms of genetic variation, all one can say is that differences exist, not that they are deleterious or advantageous. The primates include lemurs, monkeys, and apes (including humans). In primate species, the males have a larger figure than the females. Two main groups of the living primates are prosimians and anthropoids , who have more advanced traits. Prosimians are the more "primitive" - meaning they have traits seen in earlier forms. Prosimians have eyes on the side of their head and depend more on smell-–with their wet noses.
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