polygenic traits influenced by genes at 2 or more loci in the past were used to classify humans into racial groups today we know that polygenic traits are a result of adaptation global exploration increase awareness of human diversity skin color notacebly different used for racial classification Johann Blumenback emphasized five different human races based largely on skin color Biological Determinism Association between physical attributes and behavioral characteristics intelligence morals values abilities are all inherited along with skin color Phenomena governed by biological genetic factors inherit cultural and cognitive differences between human groups justification for enslavement and persecution Eugenics race improvement Late 1800s Francis Galton civilized society weakened by failure of NS to eliminate unfit inferior individuals Proponent of Eugenics race improvement government regulation of marriage family size forced sterilization jail for offenders popular during WWI 1930 s US Europe Germany Biological determinism and eugenics reflected ethnocentric views examples lighter skin color superior to darker skin color christian monotheism superior to polytheism Modern Synthesis cid 127 Mendelian genetics and Darwin s theory of NS influenced biological sciences applied evolutionary principles to study human variation humans are polytypic species we differ with regard to expression of one or more trait Concept of Race Human Variation based solely on physical appearance biological diversity might seem substantial however the entire amount of genetic diversity of the human species is very small placed into specific category according to geographic locality based on attributes skin eye color shape of face nose hair color texture since 1950 s race syonymous with species Human Race Nationality African Race Brisith Race Ethic or religious identity Jewish Race Race subspecies geographically isolated from other members of their species not geographically isolated from other members of their species cid 127 members possess characteristics not possessed by other members of their species The concept of race that uses physical attributes to classify indivuals is a cultural construction humans are the same subspecies differences are due to variation Human Biologists and Anthropologists agree some phenotypic differences between humans roughly corrspond to particular geographic regions clines recognize that race isnt a valid concept amount of genetic variation within groups is greater than variation between groups cid 127 Outward phenotypic expression still used by some example Forensic Anthropologists racial ethnic background determination 80 accurate population diversity human phenotypic variation represents a biological continuum Cline gradual shift in gene frequencies between neighboring populations thought to reflect microevolutionary changes of NS and or gene flow Clinal Model examples with blood alleles on Carmen Human Nuclear DNA cid 127 most variation occurs within populations not between them not the most accurate method today but still provides a general overview of the geographical shift in allele frequencies cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 fewer differences between races than among individuals identified as being in a particular race Racism cultural phenomenon found worldwide leads to intolerance violence warfare terrorism genocide Biological variation traces of our evolutionary past process began hundreds of thousands of years ago Contemporary Interpretations Polymorphism Loci with more than one allele different expressions of traits are result of biological genetic adaptations of hominin ancestors to their enviroments can be expressed in the phenotype as the result of gene actions ex ABO blood system or exist solely at the DNA levels within noncoding regions Phenotypically Ascertained most of these traits are subject to NS DNA based most of these characteristics are neutral and are therefore not influenced by NS Population Genetics gene pool total complement of genes shared by the reproductive members of a population breeding isolates populations that are clearly isolated geographically and or socially from other breeding populations endogamy mating with individuals from the same group exogamy mating with individuals from other groups Is evolution occurring at a given locus cid 127 measure allele frequencies for specific traits compare observed with theoretical frequencies Hardy Weinburg theory of genetic equilibrium gives theoretical cid 127 mathematical model assumes evolution is not occurring does the data show otherwise Assumptions of Hardy Weinburg population is infinitely large no genetic drift no mutation no gene flow natural selection is not operating cid 127 mating is random Hardy Wenburg How does it work Basic Info frequency of dominant allele p frequency of recessive allele q p q 1 100 of alleles at the locus in question p2 frequency of AA genotype 2pq frequency of Aa genotype q2 frequency of aa genotype If all assumptions are met no evolution is occurring is this realistic allele frequencies observed in real life are compared with frequencies expected to be seen if the specific conditions are met if observed is different than expected an evolutionary force is working to determine the expected proportions the chances of the alleles combining with one another into all possible combinations are computed the chances of all possible combinations occurring randomly can be shown as p2 2pq q2 1 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127