History of Human Genetics

Question 1

Mendel’s law of uniformity

Answer 1

Crossing two homozygotes of different alleles: progeny of first generation are identical and heterozygous

Question 2

Mendel’s law of segregation

Answer 2

2 alleles at single locus are never found in same gamete but segregate and pass to different gametes

Question 3

Mendel’s law of independence

Answer 3

Each pair of alleles acts independently during segregation into the gametes

Question 4

How Mendel’s theory differed from previous ones

Answer 4

No blending of traits: genes as discrete units
Dominant allele doesn’t destroy recessive alleles: recessives reappear in F2
Hybrid must contain both alleles

Question 5

Archibald E. Garrod

Answer 5

Studied alkaptonuria (rare disease in which homogentistic acid can't be broken down, resulting in black urine and other malformations)
Observed carrier effects (parents are carriers of alkaptonuria)

Question 6

Alfred H. Sturtevant

Answer 6

Studied under Thomas Hunt Morgan
First chromosome map created from studying fruit flies
Determined placing of genes from seeing that some traits are linked

Question 7

Results of Human Genome Project

Answer 7

Almost complete human sequence
Location and structure of most genes
Identification of most of the major variants
Highly interactive database with continuous infusion of new information

Question 8

Sir Francis Galton

Answer 8

Cousin of Darwin
Pioneered field of behavioral genetics
Believed all traits were result of genetics, without any contribution from environment

Question 9

Karl Pearson

Answer 9

Worked with Galton

Pearson’s coefficient: enables qualification of how closely related 2 things are

Question 10

Difference between biometricians and Mendelianists

Answer 10

Mendelianists: Mendel’s rules of inheritance gave evolutionary mechanism which would result in large differences
Biometricians (lead by Karl Pearson): small changes are important for evolution, focused on quantitative traits

Question 11

Eugenics

Answer 11

Using genetics to improve human race by having individuals of “good stock” breed

Question 12

Goals of eugenics

Answer 12

Avoid suffering by eliminating disease alleles

Improve human kind by increasing intelligence, strength, and health

Question 13

Eugenics in USA

Answer 13

Positive programs: encourage marriage between “fit” parents (education of public, etc.)
Negative programs: forced sterilization, no inter-racial marriage, limited immigration from “inferior” countries, containment zones for “inferior” people (mentally disabled to those with undesired behaviors such as prostitutes and feminists)
Peaked in early 20th century in response to increased immigration and racism

Question 14

Lebensunwertes Leben

Answer 14

Nazis: “Life unworthy of living”
Started out with forced sterilization, progressed to killing of disabled people and those of “inferior” races (Jews, Gypsies, Soviet and Polish citizens)

Question 15

Thomas Hunt Morgan

Answer 15

Introduced chromosomal theory of heredity
Noticed that some fly mutants didn’t assort independently: they stayed together in crosses, but some did separate eventually
Non-independent assortment meant genes could be placed in order (the more often mutants separate, the more distant those genes are)

Question 16

Human Genome Project Specifics

Answer 16

Started in 1990s
Determined haploid human DNA sequence
Studied multiple individuals, which enabled identification of sequence variation
Identified sequence location of expressed RNA (location of RNA reveals where genes are located)