Mutations & Polymorphisms - Basis for Diversity

Question 1

describe chromosome mutation, example

Answer 1

affect number of intact chromosomes (loss/gain) e.g. Trisomy 21

Question 2

describe regional mutation, example

Answer 2

alter structure of individual chromosomes/rearrange e.g. frequently in cancer, rare disease syndromes

Question 3

describe gene/DNA mutation

Answer 3

alter sequence of individual genes/DNA segments (single nucleotide, base-pair mutation)

Question 4

how do chromosome mutations form?

Answer 4

misssegregation during meiosis

Question 5

how do chromosomal rearrangements form?

Answer 5

chromosomes may break and pieces join in a new configuration

Question 6

karyotype of monosomy x

Answer 6

Turner syndrome (45, X)

Question 7

karyotype of trisomy 21

Answer 7

Down’s syndrome (47, XX + 21 or 47, XY + 21)

Question 8

karyotype of trisomy 18

Answer 8

Edward’s syndrome (47, XX + 18 or 47, XY + 18)

Question 9

karyotype of trisomy 13

Answer 9

Patan Syndrome (47,, XX + 13 or 47 XY + 13)

Question 10

karyotype of Klinefelter syndrome

Answer 10

47, XXY

Question 11

karyotype of Triple X

Answer 11

47, XXX

Question 12

karyotype of XYY syndrome

Answer 12

47, XYY

Question 13

why are there no more other trisomies known?

Answer 13

usually not viable/early lethal

Question 14

why may the consequences of a point mutation vary?

Answer 14

depend on position in genetic code

Question 15

germ cell mutation

Answer 15

mutation in the gametes, cause non-symptomatic genetic polymorphisms or inheritable diseases of many types, mutation transmitted to offspring

Question 16

somatic cell mutation

Answer 16

in somatic cells, may cause disease in individual, daughter cells, not inherited by offspring

Question 17

difference between mutation and polymorphism

Answer 17

mutation: change in DNA sequence away from normal (rare/abnormal allele), also in a single cell
polymorphism: DNA sequence variation that is common in the population (ca. 1 %)

Question 18

SNV

Answer 18

single nucleotide variant

Question 19

VNTRs

Answer 19

variable number of tandem repeats

Question 20

CNVs

Answer 20

copy number variants (variation of number of copies of larger segments of the genome)

Question 21

relationship between alleles and genotypes

Answer 21

the genotype is the combination of alleles at a DNA segment (allele and genotype frequencies may differ between populations/ethnic groups)

Question 22

why are mutations significant to evolution?

Answer 22

-alleles and phenotypes that make an organism more likely to survive/reproduce are also more likely to be transmitted to other generations

Question 23

balancing selection

Answer 23

multiple alleles are actively maintained in gene pool (by several mechanisms) e.g. heterozygous advantage

Question 24

purifying selection

Answer 24

selection against new, deleterious trait

Question 25

positive selection

Answer 25

selection for new/rare trait, spread rapidly in population

Question 26

gene flow

Answer 26

migration

Question 27

genetic drift

Answer 27

by random events