Genome Seq and Evolution, Cluster and Repeats

Question 1

Polymorphism

Answer 1

Existence of 2 or more variants

Question 2

Alleles on a gene show extensive polymorphism at sequence level, but…

Answer 2

Many sequence changes do not affect function

Question 3

Responsible for most of genetic variation between individuals?

Answer 3

SNPs

Question 4

A change in DNA sequence in a coding region that does NOT alter the amino acid encoded (faster accumulation than opposite)

Answer 4

Synonymous mutation

Question 5

A change in DNA sequence in a coding region that alters the amino acid encoded

Answer 5

Nonsynonymous mutation

Question 6

Frequency of a neutral mutation depends on…

Answer 6

Genetic drift

Question 7

Gene conversion bias

Answer 7

Increases GC content

Question 8

Mutational bias

Answer 8

High AT content (methylation of amine)

Question 9

Fixation

Answer 9

Process by which a new allele replaces the allele that was previously predominant in a population

Question 10

Small population vs large population fixation opportunity?

Answer 10

Small population = higher fixation opportunity

Question 11

Genetic hitchhiking

Answer 11

Change in frequency of a genetic variant due to its linkage to selected variant at another locus

Question 12

NS > S Substitutions

Answer 12

Positive selection

Question 13

S > NS Substitutions

Answer 13

Negative selection

Question 14

Nonrandom association between alleles at two different loci

Answer 14

Linkage disequilibrium

Question 15

______ substitutions accumulate 10x faster than ______ substitutions

Answer 15

Synonymous, nonsynonymous

Question 16

How is evolutionary divergence between DNA sequences measured?

Answer 16

Corrected % of positions at which corresponding nucleotides differ

Question 17

Genes that are unique to vertebrates are connected with…

Answer 17

Immune and nervous systems

Question 18

Duplicated genes can ______, or one copy can _______

Answer 18

Diverge to generate different genes, become an inactive pseudogene

Question 19

Globin gene clusters

Answer 19

Arose by duplication and divergence from ancestral gene that had 3 exons (alpha and beta-globin separated in early vertebrate evolution period)

Question 20

Processed pseudogenes result from…

Answer 20

Reverse transcription and integration of mRNA transcripts

Question 21

Nonprocessed pseudogenes result from…

Answer 21

Incomplete duplication or second-copy mutation from functional genes

Question 22

Increases the chromosome number by a multiple of two (gene duplication)

Answer 22

Polyploidization

Question 23

Polyploidization from mitotic or meiotic errors within a species

Answer 23

Autopolyploidy

Question 24

Polyploidization from hybridization between two different but reproductively compatible species

Answer 24

Allopolyploidy

Question 25

2R Hypothesis

Answer 25

Early vertebrate genome underwent two rounds of duplication

Question 26

Mispairing between nonallelic loci can...

Answer 26

Cause unequal crossing-over

Question 27

rDNA cluster organization

Answer 27

Transcription units alternate with nontranscribed spacers

Question 28

Nontranscribed spacers

Answer 28

Short repeating units whose number varies so lengths vary

Question 29

Ribosomal RNA (rRNA) encoded by...

Answer 29

Large number of identical genes that are tandemly repeated to form one or more clusters

Question 30

Concerted evolution

Answer 30

Explains why paralogous genes within one species are more closely related to each other than members of same gene family in another species