Genetics and Variability of Skin Color

These flashcards summarize key vocabulary terms related to the genetics and variability of skin color, including definitions and important concepts discussed in the lecture.

Melanin

The pigment responsible for skin color, with two types: eumelanin (black-brown) and pheomelanin (red-yellow).

Skin reflectance

An objective measure of skin color based on how much light bounces back, indicating darker skin reflects less light than lighter skin.

Polygenic trait

A trait controlled by multiple genes, such as skin color, which shows continuous variation.

Folate

A vitamin required for DNA synthesis and repair; deficiency can lead to neural tube defects.

Vitamin D

A fat-soluble vitamin synthesized through exposure to sunlight; essential for calcium absorption and bone health.

Selection for lighter skin

An adaptation typically found in northern regions where less sunlight requires increased skin permeability for vitamin D synthesis.

Interracial mating

Mating between individuals of different racial backgrounds that can blur social divisions and challenge racial classifications.

Scientific racism

A belief system emerging in the 19th century that used biological differences to justify social hierarchies and enslavement.

Haplotype

A group of genes inherited together from a single parent; used in the context of genetic variation among populations.

Founder effect

The reduced genetic diversity that occurs when a population is descended from a small number of ancestors.

mulato

one parent of african acestory and one european

quadroon

¼ African ¾ European

octoroon

1/8 African

españoles

european and spanish

Peninsulares

born in europe

criollos

creole, born in Americas

Indios

native american

mestizos

50/50 espanoles and indios

castizos

75/20 espanoles indios

cholos

25/75 Espanoles indios

negros

africans

negros criollos

born outside of Africa

mulatos

50/50 espanoles negro

zambos

indios/negros “sambo”

pardos

espanoles/indios/negros

micro races

an ethnic neighborhood in a large city

sororal twins

same parents, different eggs and sperm, same womb, two different colrs

cheddar man

found in southern england, dark skin blue eyes, DNA found in current man with blue eyes