biol 1040 - your inner neanderthal & the myth of biological race

where did modern humans (Homo sapiens) originate?

africa - human populations later migrated to other parts of the world

why is genetic diversity greatest overall in africa?

humans have a long evolutionary history in africa; migrating populations carried only a subset of ancestral diversity

are humans descended from modern chimpanzees?

no - humans and chimpanzees evolved from a shared common ancestor

is genetic variation greater within or between human groups?

within groups

genetic differences overlap extensively ___ populations

between

what does the lecture say about the myth of biological race?

human genetic variation does not divide people into distinct biological races

what are neanderthals and denisovans?

extinct human lineages or close relatives that interbred with ancestors of modern humans

what is gene flow

the movement of genetic variants between populations or lineages, including through interbreeding

what is the main evidence against racial purity?

human history includes migration, interbreeding, and shared ancestry among different lineages

how can ancient DNA affect modern humans?

inherited variants from ancient lineages can still influence modern genetic traits and health-related outcomes

human ancestry is __; genetic differences do not establish __ or __

interconnected; racial purity or superiority

what does it mean that human evolution is ongoing?

human populations continue to evolve through mutation, migration, natural selection, and other processes

what is a molecular clock?

a method that uses the rate of molecular change to estimate when evolutionary lineages diverged

what did mitochondrial DNA help reveal about recent human history?

it provided evidence that non-african maternal lineages descend from ancestors in africa

why is genetic diversity outside africa described as a subset of african diversity?

migrating populations carried only part of the genetic variation present in ancestral african populations

if human races were distinct lineages, what pattern would scientists expect?

groups would show clearer genetic separation and many variants largely unique to each group

what do actual patterns of human genetic variation show instead?

variation within populations is greater than variation between them, with extensive overlap

does greater variation within groups mean all populations are genetically identical?

no - populations differ in variant frequencies, but those differences do not form distinct biological races

what is hybridization in human evolutionary history?

interbreeding between individuals from different evolutionary lineages

what is introgression?

genetic material from one lineage enters another through interbreeding and persists in later generations

why is human evolutionary history more like a network than a simple tree?

different lineages sometimes interbred, allowing genes to move between branches of the evolutionary tree

what does neanderthal DNA in modern humans demonstrate?

ancestors of some modern humans interbred with neanderthals, leaving inherited genetic variants

what did the lecture say about neanderthal DNA and psychiatric traits?

some studies found associations with psychiatric outcomes; association alone does not prove causation

what did the lecture say about neanderthal DNA and COVID-19?

a neanderthal-derived variant was associated with increased risk of severe COVID-19 in some studies

do neanderthal-derived variants affect every person in the same way?

no - effects depend on the variant and other genetic, environmental, and health-related factors

what is hypoxia

a condition in which body tissues do not receive enough oxygen

what role does EPAS1 play in the tibetan high-altitude example?

a denisovan-derived EPAS1 variant is associated with adaptation to low-oxygen conditions at high altitude

what is adaptive introgression?

when a variant enters a population through interbreeding and becomes beneficial in its environment

what does denisovan-derived EPAS1 demonstrate about evolution?

interbreeding can introduce genetic variants that help populations adapt to particular environments

what is melanin, and how does it relate to skin color?

melanin is a pigment that contributes to skin color; genetic variation influences its production

why is skin color called a continuous trait?

it varies along a spectrum rather than dividing people into a few, distinct categories

how is skin pigmentation related to UV radiation?

skin pigmentation varies geographically and UV exposure has contributed to the evolution of pigmentation patterns

latitudinal clinal pattern, where darker skin is found near the equator and lighter skin closer to the poles

what do pigmentation gene variants show about african genetic diversity?

variants common outside africa can also occur in africa, supporting the idea that non-african diversity is a subset of african diversity

what is lactase persistence?

the ability to continue producing enough lactase to digest lactose into adulthood

what are lactose and lactase

lactose is the sugar in milk; lactase is the enzyme that breaks it down

how did lactase persistence evolve in europe and africa?

it evolved independently in different populations through different genetic mutations

what are LCT and MCM6 in the european lactase-persistence example?

LCT is a gene that encodes lactase, a regulatory region associated with MCM6; MCM6 helps control LCT expression

why is lactase persistence not evidence that one population is more evolved?

it is a context-specific adaptation, not a measure of overall advancement

what is the difference between adaptation and biological superiority?

adaptation is a specific trait/behavior that helps an organism survive and reproduce in its current environment, while biological superiority is a false belief that one species/group is more advanced than another

what does the lecture say about science and racism?

modern genetics proves human racial purity and superiority are myths, while acknowledging that historical science was actively used to justify racism and discrimination.