Genetics Vocab Ch. 9 Of Pierce 3Rd Ed

Front 1

acentric chromatid

Back 1

lacks a centromere; produced when crossing over takes place within a paracentric inversion. The acentric chromatid does not attach to a spindle fiber and does not segregate in meiosis or mitosis; so it is usually lost after one or more round of cell division

Hint 1

244

Front 2

acrocentric chromosome

Back 2

chromosome in which the centromere is near one end, producing a long arm at one end and a knob, or satellite, at the other end

Hint 2

238

Front 3

adjacent-1 segregation

Back 3

type of segregation that takes place in a heterozygote for a translocation. If the original, nontranslocated chromosomes are N1 and N2 and the chromosomes containing the translocated segments are T1 and T2, then adjacent-1 segregation takes place when N1 and T2 move toward one pole and T1 and N2 move toward the oposite pole

Hint 3

247

Front 4

adjacent-2 segregation

Back 4

type of segregation that takes place in a heterozygote for a translocation. If the original, nontranslocated chromosomes are N1 and N2 and the chromosomes containing the translocated segments are T1 and T2, then adjacent-2 segregation takes place when N1 and T1 move toward one pole and T2 and N2 move toward the opposite pole

Hint 4

247

Front 5

allopolyploidy

Back 5

condition in which the sets of chromosomes of a polyploid individual possesing more than two haploid sets are derived from two or more species

Hint 5

255

Front 6

alternate segregation

Back 6

type of segregation that takes place in a heterozygote for a translocation. If the original, nontranslocated chromosomes are N1 and N2 and the chromosomes containing the translocated segments are T1 and T2, then alternate segregation takes place when N1 and N2 move toward one pole and T1 and T2 move toward the opposite pole

Hint 6

247

Front 7

amphidiploidy

Back 7

type of allopolyploidy in which two different diploid genomes are combined, so that every chromosome has one and only one homologous partner and the genome is functionally diploid

Hint 7

257

Front 8

aneuploidy

Back 8

change from the wild type in the number of chromosomes; most often an increase or decrease of one or two chromosomes

Hint 8

249

Front 9

autopolyploidy

Back 9

condition in which all the sets of chromosomes of a polyploid individual possessing more than two haploid sets are derived from a single species

Hint 9

255

Front 10

chromosome deletion

Back 10

loss of a chromosome segment

Hint 10

242

Front 11

chromosome duplication

Back 11

mutation that doubles a segment of a chromosome

Hint 11

240

Front 12

chromosome inversion

Back 12

rearrangement in which a segment of a chromosome has been inverted 180 degrees

Hint 12

244

Front 13

chromosome mutation

Back 13

difference from the wild type in the number or structure of one or more chromosomes; often affects many genes and has large phenotypic effects

Hint 13

238

Front 14

chromosome rearrangement

Back 14

change from the wild type in the structure of one or more chromosomes

Hint 14

240

Front 15

dicentric bridge

Back 15

structure produced when the two centromeres of a dicentric chromatid are pulled toward opposite poles, stretching the dicentric chromosome across the center of the nucleus. Eventually, the dicentric bridge breaks as the two centromeres are pulled apart

Hint 15

245

Front 16

dicentric chromatid

Back 16

chromatid that has two centromeres; produced when crossing over takes place within a paracentric inversion. The two centromeres of the dicentric chromatid are frequently pulled toward opposite poles in mitosis or meiosis, breaking the chromosome

Hint 16

244

Front 17

displaced duplication

Back 17

chromosome rearrangement in which the duplicated segment is some distance from the original segment, either on the same chromosome or on a different one

Hint 17

240

Front 18

Down syndrome (trisomy 21)

Back 18

characterized by variable degrees of mental retardation, characteristic facial features, some retardation of growth and development, and an increased incidence of heart defects, leukemia, and other abnormalities; caused by the duplication of all or part of chromosome 21

Hint 18

251

Front 19

Edward syndrome (trisomy 18)

Back 19

characterized by severe retardation, low set ears, a short neck, deformed feet, clenched fingers, heart problems, and other disabilities; results from the presence of three copies of chromosome 18

Hint 19

252

Front 20

familial Down syndrome

Back 20

caused by a Robertsonian translocation in which the long arm of chromosome 21 is translocated to another chromosome; tends to run in families

Hint 20

251

Front 21

fragile site

Back 21

constriction or gap that appears at a particular location on a chromosome when cells are cultured under special conditions. One fragile site on the human X chromosome is associated with mental retardation (fragile-X syndrome) and results from an expanding trinucleotide repeat

Hint 21

247

Front 22

gynandromorph

Back 22

individual organism that is a mosaic for the sex chromosomes, possessing tissues with different sex-chromosome constitutions

Hint 22

254

Front 23

haploinsufficient gene

Back 23

must be present in two copies for normal function. If one copy of the gene is missing, a mutant phenotype is produced.

Hint 23

242

Front 24

haploinsufficiency

Back 24

the appearance of a mutant phenotype in an individual cell or organism that is heterozygous for a normally recessive trait

Hint 24

242

Front 25

metacentric chromosome

Back 25

chromosome in which the two chromosome arms are approximately the same length

Hint 25

238

Front 26

monosomy

Back 26

absence of one of the chromosomes of a homologous pair

Hint 26

249

Front 27

mosaicism

Back 27

condition in which regions of tissue within a single individual have different chromosome constitutions

Hint 27

254

Front 28

nonreciprocal translocation

Back 28

movement of a chromosome segment to a nonhomologous chromosome or region without any (or with unequal) reciprocal exchange of segments

Hint 28

246

Front 29

nullisomy

Back 29

absence of both chromosomes of a homologous pair (2n-2)

Hint 29

249

Front 30

paracentric inversion

Back 30

chromosome inversion that does not include the centromere in the inverted region

Hint 30

244

Front 31

Patau syndrome (trisomy 13)

Back 31

characterized by severe mental retardation, a small head, sloping forehead, small eyes, cleft lip and palate, extra fingers and toes, and other disabilities; results from the presence of three copies of chromosome 13

Hint 31

253

Front 32

pericentric inversion

Back 32

chromosome inversion that includes the centromere in the inverted region

Hint 32

244

Front 33

polyploidy

Back 33

possession of more than two haploid sets of chromosomes

Hint 33

249

Front 34

position effect

Back 34

dependence of the expression of a gene on the gene's location in the genome

Hint 34

244

Front 35

primary Down syndrome

Back 35

caused by the presence of three copies of chromosome 21

Hint 35

251

Front 36

pseudodominance

Back 36

expression of a normally recessive allele owing to a deletion on the homologous chromosome

Hint 36

242

Front 37

reciprocal translocation

Back 37

reciprocal exchange of segments between two nonhomologous chromosomes

Hint 37

246

Front 38

reverse duplication

Back 38

duplication of a chromosome segment in which the sequence of the duplicated segment is inverted relative to the sequence of the original segment

Hint 38

240

Front 39

Robertsonian translocation

Back 39

translocation in which the long arms of two acrocentric chromosomes become joined to a common centromere, resulting in a chromosome with two long arms and usually another chromosome with two short arms

Hint 39

247

Front 40

submetacentric chromosome

Back 40

chromosome in which the centromere is displaced toward one end, producing a short arm and a long arm

Hint 40

238

Front 41

tandem duplication

Back 41

duplication of a chromosome segment that is adjacent to the original segment

Hint 41

240

Front 42

telocentric chromosome

Back 42

chromosome in which the centromere is at or very near one end

Hint 42

238

Front 43

tetrasomy

Back 43

presence of two extra copies of a chromosome (2n+2)

Hint 43

249

Front 44

translocation

Back 44

movement of a chromosome segment to a nonhomologous chromosome or to a region within the same chromosome. Also, movement of a ribosome along mRNA in the course of translation

Hint 44

246

Front 45

translocation carrier

Back 45

individual organism heterozygous for a translocation

Hint 45

252

Front 46

trisomy

Back 46

presence of an additional copy of a chromosome (2n+1)

Hint 46

249

Front 47

trisomy 8

Back 47

presence of three copies of chromosome 8; in humans, results in mental retardation, contracted fingers and toes, low-set malformed ears, and a prominent forehead

Hint 47

253

Front 48

unbalanced gametes

Back 48

gamete that has a variable number of chromosomes; some chromosomes may be missing and others may be present in more than one copy

Hint 48

256

Front 49

uniparental disomy

Back 49

inheritance of both chromosomes of a homologous pair from a single parent

Hint 49

254