Genetics, Twins, and Epigenetics

What is a zygote?

Fertilized egg that is formed from union of sperm and egg cells in human reproduction

What is a gene?

Basic unit of genetic instruction

What is a chromosome?

Molecules of DNA that hold the genetic instructions for every cell in the body.

What are monozygotic twins?

Identical

Originate from same zygote

What are dizygotic twins?

Fraternal

Originate from fertilization of two separate eggs around the same time

What are teratogens?

Environmental agents such as drugs and viruses, diseases, and physical conditions that impair prenatal development and lead to birth defects and sometimes death.

GRIGGS, RICHARD A.. Psychology: A Concise Introduction (p. 668). Worth Publishers. Kindle Edition.

What is fetal alcohol syndrome?

A syndrome affecting infants whose mothers consumed large amounts of alcohol during pregnancy, resulting in a range of severe effects, including intellectual disability and facial abnormalities.

GRIGGS, RICHARD A.. Psychology: A Concise Introduction (p. 669). Worth Publishers. Kindle Edition.

What is the nature vs nurture debate?

Twin studies have shown development is based on both nature (genetics) and nurture (environment)

What is heritability?

Proportion of phenotypic variation that is due to genetic factors

What is a reaction range?

The genetically determined limits for an individual’s intelligence.

GRIGGS, RICHARD A.. Psychology: A Concise Introduction (p. 635). Worth Publishers. Kindle Edition.

What is the Flynn effect?

The finding that the average intelligence test score in the United States and other industrialized nations has improved steadily over the last century.

GRIGGS, RICHARD A.. Psychology: A Concise Introduction (p. 638). Worth Publishers. Kindle Edition.

What are molecular genetics?

Looks for genes associated with a psychological trait

A trait’s variation comes from many genes with small effects

Asks: what genes?

What is behavioral genetics?

Looks at effects of genes and environment on individual differences in a characteristics

Asks: how much is genetic?

Uses: twin studies, adoption studies

What is the heritability of intelligence, extroversion, major depression, schizophrenia, and morning/evening-ness?

Intelligence at 18: 0.82

Extroversion: 0.5

Major depression: 0.37

Schizophrenia: 0.8

Morning/evening-ness: 0.23

What are epigenetics?

Studies the influences of gene expression and what determines that

What is transgenerational transmission?

Mother creates fetus → fetus has reproductive cells that were also created by the mother → eventually leads to a child

Three generations of transmission