Chapter 13

Question 1

Progeny that exhibit the same allele combinations as parents

Answer 1

Parental type

Question 2

result from nonhomologous recombination in Meiosis

Answer 2

non-parental type

Question 3

study of genomes

Answer 3

genomics

Question 3

process by which homologous chromosomes undergo reciprocal physical exchanges at their arms, also crossing over

Answer 3

homologous recombination

Question 4

finding the location of genes on each given chromosome

Answer 4

genomic mapping

Question 5

failure of synapsed homologs to completely separate and migrate to separate poles during the meiosis’ first cell division

Answer 5

nondisjunction

Question 6

an individual’s chromosome number and appearance; includes the size, banding patterns, and centromere position

Answer 6

karyotype

Question 7

individual with the appropriate number of chromosomes for their species

Answer 7

euploid

Question 8

individual with an error in chromosome number; includes chromosome segment deletions and duplications

Answer 8

aneuploid

Question 9

otherwise diploid genotype in which one chromosome is missing

Answer 9

monosomy

Question 10

otherwise diploid genotype in which one entire chromosome duplicates

Answer 10

trisomy

Question 11

amount of gene products coded for

Answer 11

gene dose

Question 12

individual with an incorrect number of chromosome sets

Answer 12

polyploid

Question 13

condensing X chromosomes into Barr bodies during embryonic development in females to compensate for the double genetic dose

Answer 13

X inactivation

Question 14

detachment, 180° rotation, and chromosome arm reinsertion

Answer 14

Inversion

Question 15

segment of a chromosome dissociates and reattaches to a different chromosome

Answer 15

Translocation

Question 16

inversion that involves the centromere

Answer 16

Pericentric

Question 17

inversion that occurs outside the centromere

Answer 17

Paracentric

Question 18

What were the two key experiments that led scientists to the Chromosomal Theory of Inheritance?

Answer 18

Theodor Boveri-embryonic development of sea urchins doesnt occur unless chromosomes are present
Walter Sutton-seperation of chromosomes in meiosis

Question 19

What did the Chromosomal Theory of Inheritance say?

Answer 19

chromosomes are the genetic material responsible for mendelian inheritance

Question 20

Who was the scientist who provided most of the scientific evidence in support of the theory? What species of animal did he work with?

Answer 20

Thomas Hunt Morgan, fruit fly

Question 21

What was the significance for Morgan of finding two physical mutations that arose from genes on the same chromosome? What genetic questions did this allow him to study? How did Morgan test these questions? What did his experiment consist of? What did the results indicate?

Answer 21

he could study how genes moved with chromosomes and how genes moved in relation to other genes on the same chromosome; he demonstrated random segragation and genes on the same chromosome disrupted predicted frequency of traits; indicated linked genes

Question 22

What are parental types? Under what circumstances would you expect to see them in the chromosomes of offspring?

Answer 22

offspring have same allele combinations as parents; linkage occured

Question 23

What are non-parental types? Under what circumstances would you expect to see them in the chromosomes of offspring?

Answer 23

chromosomes with combinations of alleles not seen in the parent; this followed mendels laws

Question 24

Who is Frans Janssen and what did he observe?

Answer 24

synapsis events and suggested that chromosomes may physically exchange segments in meiosis

Question 25

Who is Alfred Sturtevant and what were his contributions to genetics?

Answer 25

undegrad in morgans lab, created first chromosome map

Question 26

What two assumptions did Sturtevant make about genes?

Answer 26

genes are ordered serially on thread like chromosomes the incidence of crossing over between two homologous chromosomes could occur with equal liklihood anywhere along the length of the chromosome

Question 27

What where Sturtevant’s hypotheses?

Answer 27

the average number of crossovers between alleles correlated with their genetic distance from each other, relative to the locations of other genes on the chromosome

Question 28

If a genetic cross tracking two traits produces parental types 90 times out of 100, what is the likelihood of homologous recombination?

Answer 28

10%

Question 29

On a genetic map, how are the frequencies of homologous recombination related to the placement of genes on the map?

Answer 29

Close together has a lower recombination frequency and a lower chance the genes are swapped in crossing over

Question 30

When the frequency of producing parental types approaches 0.5, it becomes less accurate in predicting linkage. Why is this?

Answer 30

.5 is the largest possible because more than that would be unclear if far apart or on other chromosome

Question 31

What are the two broad ways that chromosomal abnormalities can happen?

Answer 31

1. Abnormalities in chromosome number 2. Chromosomal structural rearrangements

Question 32

Why are chromosomal abnormalities usually of such high consequence?

Answer 32

Small segments of chromosomes can span many genes that would be altered

Question 33

What is a karyotype?

Answer 33

Visualization of chromosomes in a cell where homologous pairs are in numerical order

Question 34

What is the primary cause of all disorders in chromosome number?

Answer 34

Nondisjunction-chromosomes do not separate correctly

Question 35

Name two examples of how nondisjunction could happen.

Answer 35

Misaligned or incomplete synapsis Disfunction of the spindle apparatus

Question 36

What are the results of non-disjunction if it occurs in meiosis I vs. meiosis II?

Answer 36

Meiosis I= 2 diploid gametes, 2 gametes with 0 chromosomes Meiosis II=2 normal haploid gametes, 1 diploid gamete, one gamete with 0 chromosomes

Question 37

What do we call an individual who has an error in chromosome number?

Answer 37

aneuploid

Question 38

What is monosomy? What is trisomy?

Answer 38

Monosomy=loss of 1 chromosome (typically don’t develop) Trisomy=gain of an extra chromosome

Question 39

What is the most common type of trisomy? Why is it less lethal than trisomy involving other chromosomes?

Answer 39

Down Syndrom/Trisomy 21; 21 is the shortest autosomal chromosome

Question 40

What is gene dose? How does it affect the outcome of chromosomal abnormalities?

Answer 40

Amount of configuration; extra does can lead to functional challenges for the organism

Question 41

What do we call an organism with multiple sets of all their chromosomes?

Answer 41

polyploid

Question 42

What types of organisms successfully utilize polyploid genomes?

Answer 42

Plants are the best but flatworms, fish, amphibians, lizards, and crustaceans can but will be sterile

Question 43

Why is nondisjunction is sex chromosomes less lethal than in autosomes?

Answer 43

X-inactivation, one X chromosome will inactivate by tightly condensing into a Barr body

Question 44

What is a Barr body and where does it come from?

Answer 44

Dormant, inactive X-chromosome that is tightly condensed

Question 45

What happens if an individual inherits multiple X chromosomes?

Answer 45

One is inactivated and there are mild mental/physical side effects with sterility

Question 46

What happens if an individual inherits no X chromosome?

Answer 46

Non-viable

Question 47

What is Triple-X Syndrome? What are the physical traits?

Answer 47

3 X chromosome, physically female but developmentally delayed and reduced in fertility

Question 48

What is Klinefelter Syndrome? What are the physical traits?

Answer 48

XXY, physically male with small testes, enlarged breasts, reduced body hair

Question 49

What is Turner Syndrome? What are the physical traits?

Answer 49

X0, physically female with webbed skin in the neck, short stature, hearing deficits, cardiac problems, and sterility

Question 50

What causes Cri-du-chat and what are the physical traits?

Answer 50

deletion of most of the small arm of chromosome 5, infants have a high pitched cry; nervous and cardiac abnormalities with identifiable physical features

Question 51

How are abnormalities in structural arrangement different from other forms of chromosomal abnormalities?

Answer 51

Move genes and rearrange sections of the chromosome, typically more mild

Question 52

How are inversions and deletions different? How are they similar?

Answer 52

inversions are flipped 180 with relatively more mild while deletion is to get rid of

Question 53

What do the terms pericentric and paracentric refer to? Which scenario may result in a visible lengthening of one of the chromosome arms?

Answer 53

Pericentric include the centromere while Paracentris is outside the centromere. Pericentric tends to make longer an is easier to see in a karyotype

Question 54

Which chromosomal abnormality has been associated with Schizophrenia?

Answer 54

translocations