Chapter 6

Question 1

Chromosomal Modifications (aberrations)

Answer 1

change in total chromosome number, deletion or duplication of genes or segments of chromosome, or rearrangements of genetic material

Question 2

Aneuploidy

Answer 2

organism gains/loses one or more chromosome from diploid genome

Question 3

Monosomy

Answer 3

loss of single chromosome from diploid genome

Question 4

Euploidy

Answer 4

complete haploid sets of chromosomes are present

Question 5

Polyploidy

Answer 5

more than two sets of chromosomes are present

Question 6

Nondisjunction

Answer 6

chromosomal variation originating from random errors during gamete production

Question 7

Haploinsufficiency

Answer 7

single copy of recessive gene is insufficient to provide life-sustaining function for an organism

Question 8

Trisomy

Answer 8

(2n+1) extra chromosome produces more viable organism than loss of chromosome

Question 9

Down syndrome Critical Region (DSCR)

Answer 9

critical region on chromosome 21, contains dosage-sensitive genes

Question 10

Amniocentesis and Chorionic Villus Sampling (CVS)

Answer 10

uses fetal cells obtained from amniotic fluid or placental chorion

Question 11

Noninvasive Prenatal Genetic Diagnosis (NIPGD)

Answer 11

new approach to deriving fetal cells, cells are cultured, karyotype determined by cytogenetic analysis

Question 12

Familial Down Syndrome

Answer 12

Down syndrome runs in families, translocation of chromosome 21

Question 13

Polyploidy

Answer 13

instances in which more than two multiples of haploid chromosome sets are found, more common in plants than animals

Question 14

Autopolyploidy

Answer 14

each additional set of chromosomes identical to parental species

Question 15

Autotriploids

Answer 15

arise due to failure of chromosomes to segregate during meiotic division produce diploid gamete

Question 16

Deletions and Duplications

Answer 16

total amount of genetic information in chromosome can change

Question 17

Inversions

Answer 17

genetic material is exchanged with segment of non homologous chromosome or transferred to another chromosome

Question 18

Translocation

Answer 18

location of genes altered within genome

Question 19

Structural Changes in Chromosomes

Answer 19

due to one or more breaks along chromosomal axis, followed by loss or rearrangement of genetic material

Question 20

Deletion or compensation loop

Answer 20

synapsis occur between normal homolog and chromosome with intercalary deletion

Question 21

Cri du Chat

Answer 21

loss or deletion of small variable part of short arm on chromosome 5

Question 22

Duplication

Answer 22

repeated segments, arise through unequal crossing over between synapsed chromosomes during meiosis

Question 23

Evolution by Gene Duplication

Answer 23

gene duplication essential to origin of new genes during evolution

Question 24

DNA Commonality

Answer 24

discovery of genes with substantial amount of organization and DNA sequence in common (ex various forms of hemoglobin)

Question 25

Multigene Families

Answer 25

groups of contiguous genes, products have similar function

Question 26

Inversions

Answer 26

chromosome flips 180, no loss of information

Question 27

Paracentric Inversion

Answer 27

does not include centromere

Question 28

Pericentric Inversion

Answer 28

includes centromere

Question 29

Reciprocal translocation

Answer 29

exchange of segments between two non homologous chromosomes

Question 30

Alternate Segregation

Answer 30

leads to normal and balanced gametes

Question 31

Adjacent Segregation

Answer 31

leads to gametes containing duplications and deficiencies

Question 32

Robertsonian Translocation

Answer 32

new large submetacentric or metacentric chromosome produced from translocation

Question 33

Fragile Sites

Answer 33

in studies, observations of metaphase chromosomes showed unstained regions (gaps)

Question 34

Fragile-X Syndrome

Answer 34

individuals folate-sensitive site on X chromosome