Genetics of Humanness Blake Constant Are we really

Genetics of Humanness Blake Constant

Are we really 99% chimp? Research tells us that the human and chimp genome sequences are nearly 99% identical with at least 1/3 of proteins being the same BUT is it really that simple? If we were to match up the human genome sequence with the chimp genome sequence would they mirror each other with 99% accuracy?

Modern Synthesis/Neo-Darwinism gene-centric view of evolution that believes that humans evolved from chimps solely based upon random genetic mutations that produced gradual change through the process of natural selection 4 main proponents of the original theory: - Genetic change is random - Genetic change is gradual - Natural selection is solely responsible for particular gene variations - Impossibility of inheritance of acquired characteristics

Integrative Synthesis Molecular genetics and genome sequencing have reintroduced physiological function and environmental interaction to the view of evolution influencing the speed and nature of inherited change Nobel prize winner Barbara Mc. Clintock introduced idea that the genome is an “organ of the cell” Jean-Baptist Lamarck was an early evolutionist who proposed that life forms could acquire information from their environment and pass it on in their genes

Epigenetics and Evolutionary studies have shifted from simple sequence comparisons to more in-depth analysis where gene regulation is key to understanding the evolution of humans from chimpanzees DNA methylation is the most prevalent chemical modification of genomic DNA Ape ancestor # of unique methylated genes HUMANS 171 CHIMPS 101 BONOBOS 101 GORILLAS 101 ORANGUTANS 450

Brain Differences These [TSS chromatin] networks in the human brain thought to play an important role in cognitive processes and neurological disorders Important to note that the epigenome is tissue-specific and the patterns vary between the types of cells that are studied One key area of interest was the promoter region—the area preceding a gene that controls its function like a genetic switch.

Genetic change is random/gradual Genetic change is NOT random and often not gradual rates of epigenetic mutations, such as DNA methylation, are much higher than rates of mutations transmitted genetically and are easily reversed Genetic regulation leads to genetic mutation based on evolutionary adaptation to external influences

Natural selection is responsible for particular gene variations Trans-generational epigenetic inheritance In Modern synthesis the germ-line was believed to be isolated from any influence by the rest of the organism and its response to the environment epigenetic conservation in evolutionary timescale is linked to functional conservation epigenetic divergence between closely related species may be related to functional specificity

Germ-line modifications Charles Darwin proposed that there existed particles of inheritance, called “gemmules” or “pangenes, ” that carried information of inheritance to the sexual elements and that these particles may be modifiable by the environment Testes show the highest quantity of transcription in the body Where brain tissue shows the second highest rate by a large extent less

Nutrition and Epigenetics Our health is not only determined by what we eat, but also what our parents ate. So if a pregnant mother's diet can affect the child's epigenetic outcome, can dad's diet do the same? Records show that food availability between the ages of nine and twelve for the paternal grandfather affected the lifespan of his grandchildren. BUT not in the way you might think…

Why are we so different from each other if we all share the same DNA? WHAT MAKES US UNIQUE? Why are we no longer covered in fur? Why do we have different variations in skin tone? How did our skulls change shape from our ancestors? Why are identical twins not identical? Why do some people hate the taste of certain foods? EPIGENETICS IS THE ANSWER

Neo-Darwinism VERSUS Epigenetics From a psychological perspective this can be view much like the argument for nature versus nurture The Greek prefix “epi” means “on top of” or “over”