Chapter 15

Question 1

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

Answer 1

Aneuploidy

Question 2

A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome

Answer 2

Barr Body

Question 3

A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.

Answer 3

Chromosome Theory of Inheritance

Question 4

The reciprocal exchange of genetic material between nonsister chromatids during phrophase I of meiosis.

Answer 4

Crossing Over

Question 5

A human genetic disease caused by the presence of an extra chromosome 21; characterized by mental retardation and heart and respiratory defects.

Answer 5

Down Syndrome

Question 6

A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.

Answer 6

Duchenne Muscular Dystrophy

Question 7

An ordered list of genetic loci (genes or other genetic markers) along a chromosome.

Answer 7

Genetic Map

Question 8

A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent.

Answer 8

Genomic Imprinting

Question 9

A human genetic disease caused by a sex-linked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury.

Answer 9

Hemophilia

Question 10

Genes located close enough together on a chromosome that they tend to be inherited together.

Answer 10

Linked Genes

Question 11

A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.

Answer 11

Linkage Map

Question 12

A unit of measurement of the distance between genes. One ___ ___ is equivalent to a 1% recombination frequency.

Answer 12

Map Unit

Question 13

Referring to a cell that has only one copy of a particular chromosome instead of the normal two.

Answer 13

Monosomic

Question 14

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other.

Answer 14

Nondisjunction

Question 15

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.

Answer 15

Polyploidy

Question 16

An offspring whose phenotype differs from that of the parents; also refers to the phenotype itself.

Answer 16

Recombinant Type (Recombinant)

Question 17

A gene located on a sex chromosome (usually the X chromosome), resulting in a a distinctive pattern of inheritance.

Answer 17

Sex-Linked Gene

Question 18

Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.

Answer 18

Trisomic