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Witness to Evolution Regents Biology 2006-2007 Witness to Evolution Peppered Moth 2 types: dark vs. light Peppered moth Regents Biology Peppered moth: Evolution in action Year % dark % light 1848 5 95 clean air, light-colored bark 1895 98 2 pollution, dark-colored bark 1995 19 81 Clean Air Act, light-colored bark industrial melanism Regents Biology Peppered moth Why did the population change? early 1800s = pre-industrial England low pollution lichen on trees = light colored bark late 1800s = industrial factories = soot coated trees killed lichen = dark colored bark mid 1900s = pollution controls clean air laws return of lichen = light colored bark Regents Biology What data from the Genome Project can tell us about evolution of humans Regents Biology Chromosome Numbers in the great apes: human (Homo) chimpanzee (Pan) gorilla (Gorilla) orangutan (Pogo) 46 48 48 48 Change in chromosome number? If these organisms share a common ancestor, then is there evidence in the genome for this change in chromosome number Regents Biology Ancestral Chromosomes Chromosome Numbers in the great apes (Hominidae): human (Homo) chimpanzee (Pan) gorilla (Gorilla) orangutan (Pogo) 46 48 48 48 Fusion Homo sapiens Inactivated centromere Telomere sequences Centromere Telomere Testable prediction: If common ancestor had 48 chromosomes (24 pairs) then humans carry a fused chromosome; or If common ancestor had 46 chromosomes (23 pairs) then apes carry Regents Biologya split chromosome. Human Chromosome #2 shows the exact point at which this fusion took place Homo sapiens Inactivated centromere Telomere sequences Chr 2 “Chromosome 2 is unique to the human lineage of evolution, having emerged as a result of head-tohead fusion of two acrocentric chromosomes that remained separate in other primates. The precise fusion site has been located in 2q13–2q14.1 (ref. 2; hg 16:114455823 – 114455838), where our analysis confirmed the presence of multiple subtelomeric duplications to chromosomes 1, 5, 8, 9, 10, 12, 19, 21 and 22 (Fig. 3; Supplementary Fig. 3a, region A). During the formation of human chromosome 2, one of the two centromeres became inactivated (2q21, which corresponds to the centromere from chimp chromosome 13) and the centromeric structure quickly deterioriated (42).” Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434: 724 – 731. Regents Biology In case you had any doubts… Regents Biology Evolution is "so overwhelmingly established that it has become irrational to call it a theory." -- Ernst Mayr What Evolution Is 2001 Professor Emeritus, Evolutionary Biology Harvard University (1904-2005) Regents Biology 2006-2007 Survival of the Fittest Regents Biology