Ch. 4 -- Genes And Their Evolution: Population Genetics

Question 1

Abnormal hemoglobin

Answer 1

Hemoglobin altered so that it is less efficient in binding to and carrying oxygen

Question 2

Admixture

Answer 2

The exchange of genetic material between two or more populations

Question 3

Balanced polymorphism

Answer 3

Situation in which selection maintains two or more phenotypes for a specific gene in a population

Question 4

Capillaries

Answer 4

Small blood vessels between the terminal ends of arteries and the veins

Question 5

Deme

Answer 5

A local population of organisms that have similar genes, interbreed, and produce offspring

Question 6

Directional selection

Answer 6

Selection for one allele over the other alleles, causing the allele frequencies to shift in one direction

Question 7

Disruptive selection

Answer 7

Selection for both extremes of the phenotypic distribution

May eventually lead to a speciation event

Question 8

Endogamous

Answer 8

Refers to a population in which individuals breed only with other members of the population

Question 9

Equilibrium

Answer 9

A condition in which the system is stable, balanced, and unchanging

Question 10

Exogamous

Answer 10

Refers to a population in which individuals breed only with nonmembers of their population

Question 11

Fitness

Answer 11

Average number of offspring produced by parents with a particular genotype compared to the number of offspring produced by parents with another genotype

Question 12

Founder effect

Answer 12

The accumulation of random genetic changes in a small population that has become isolated from the parent population due to the genetic input of only a few colonizers

Question 13

Frameshift mutation

Answer 13

The change in a gene due to the insertion or deletion of one or more nitrogen bases, which causes the subsequent triplets to be rearranged and the codons to be read incorrectly during translation

Question 14

Gene pool

Answer 14

All the genetic information in the breeding population

Question 15

Glucose-6-phosphate dehydrogenase (G6PD)

Answer 15

An enzyme that aids in the proper functioning of red blood cells; its deficiency, a genetic condition, leads to hemolytic anemia

Question 16

Hardy-Weinberg Law of Equilibrium

Answer 16

A mathematical model in population genetics that reflects the relationship between frequencies of alleles and of genotypes

Can be used to determine whether a population is undergoing evolutionary changes

Question 17

Hemoglobinopathies

Answer 17

A group of related genetic blood diseases characterized by abnormal hemoglobin

Question 18

Hemolytic anemias

Answer 18

Conditions of insufficient iron in the blood due to the destruction of red blood cells resulting from genetic blood diseases, toxins, or infectious pathogens

Question 19

Huntington’s chorea

Answer 19

A rare genetic disease in which the central nervous system degenerates and the individual loses control over voluntary movements, with the symptoms often appearing between ages of 30 and 50

Question 20

Induced mutations

Answer 20

Refers to those mutations in the DNA resulting from exposure to toxic chemicals or to radiation

Question 21

Klinefelter’s syndrome

Answer 21

A chromosomal trisomy in which males have an extra X-chromosome, resulting in an XXY condition

Affected individuals typically have reduced fertility

Question 22

Macroevolution

Answer 22

Large-scale evolution, such as a speciation event, that occurs after hundreds or thousands of generations

Question 23

Melanic

Answer 23

Refers to an individual with high concentrations of melanin

Question 24

Microevolution

Answer 24

Small-scale evolution, such as changes in allele frequency, that occurs from one generation to the next

Question 25

Mutagens

Answer 25

Substances, such as toxins, chemicals, or radiation, that may induce genetic mutations

Question 26

Nonmelanic

Answer 26

Refers to an individual with low concentrations of melanin

Question 27

Nonsynonymous point mutation

Answer 27

A point mutation that creates a triplet coded to produce a different amino acid than that of the original triplet

Question 28

Point mutations

Answer 28

Replacements of a single nitrogen base with another base, which may or may not affect the amino acid for which the triplet codes

Question 29

Positive selection

Answer 29

Process in which advantageous genetic variants quickly increase in frequency in a population

Question 30

Reproductive isolation

Answer 30

Any mechanism that prevents two populations from interbreeding and exchanging genetic material

Question 31

Sickle-cell anemia

Answer 31

A genetic blood disease in which the red blood cells become deformed and sickle-shaped, decreasing their ability to carry oxygen to tissues

Question 32

Spontaneous mutation

Answer 32

Random changes in DNA that occur during cell division

Question 33

Stabilizing selection

Answer 33

Selection against the extremes of the phenotypic distribution, decreasing the genetic diversity for this trait in the population

Question 34

Synonymous point mutation

Answer 34

A neutral point mutation in which the substituted nitrogen base creates a triplet coded to produce the same amino acid as that of the original triplet

Question 35

Thalassemia

Answer 35

A genetic blood disease in which the hemoglobin is improperly synthesized, causing the red blood cells to have a much shorter lifespan

Question 36

Transposable elements

Answer 36

Mobile pieces of DNA that can copy themselves into entirely new areas of the chromosomes