Chapter 15: Chromosomal Basis of Inheritance

Question 1

Morgan’s explanation for incomplete linkage

Answer 1

Cross over of homologous chromosomes

Question 2

genomic imprinting

Answer 2

when certain genes are silenced depending on which parent they came from

may result from adding a CH3 to cysteine nucleotides

Question 3

duplication

Answer 3

1 of 4 types of chromosome alterations

when a chromosomal segment gets duplicated

Question 4

Centimorgan

Answer 4

the distance between genes
represents 1% recombination frequency
the farther apart they are, the more likely there will be a cross over between them
aka map unit

Question 5

Wild type

Answer 5

The ‘normal’ phenotype for a trait

exp. red eye flies

Question 6

Aneuploidy

Answer 6

When an offspring has an abnormal number of a particular chromosome because of mitotic nondisjunction.

exp. trisomy 21, Turner’s syndrome

Question 7

4 types of chromosome alterations

Answer 7

1. deletion
2. duplication
3. inversion
4. translocation

Question 8

Mutant

Answer 8

The alternative prototype to the wild type

exp. white eyed flies

Question 9

Expression of recessive x-linked genes (likelihood)

Answer 9

More likely in XY offspring because they don’t have another X to cancel out the first X

exp. color blindness and hemophilia

Question 10

Incomplete linkage

Answer 10

The idea that genes can be linked even if some recombinant phenotypes are observed

Question 11

Barr body

Answer 11

what female mammals’ second X chromosome shrivels up into as it inactivates

Question 12

inversion

Answer 12

1 of 4 types of chromosome alterations

when a segment of a chromosome gets reversed

Question 13

Miscarriage

Answer 13

can occur in the event of dramatic errors/large scale chromosomal changes

exps. chromosome number or structure

Question 14

Linked genes

Answer 14

Genes on the same chromosome that tend to be inherited together

Question 15

Recombined type

Answer 15

when an offspring has new combinations of traits

aka recombinants

Question 16

Mitotic Nondisjunction

Answer 16

when pairs of homologous sister chromatids do not separate properly

Question 17

X Inactivation

Answer 17

when female mammals’ second X chromosome inactivates, and condenses into a barr body

Results in mosaic expression of whatever heterozygous genes are located her X

Question 18

Linkage map

Answer 18

genetic map of a chromosome based on recombination frequencies

Question 19

deletion

Answer 19

1 of 4 types of chromosome alterations

when a chromosomal segments gets deleted. bad news bears.

Question 20

Map units

Answer 20

the distance between genes
represents 1% recombination frequency
the farther apart they are, the more likely there will be a cross over between them
aka centimorgan

Question 21

Parental type

Answer 21

when an offspring’s phenotype matches on of their parients’

Question 22

Pure breed/true breed

Answer 22

Homozygous

Question 23

translocation

Answer 23

1 of 4 types of chromosome alterations

when a segment of a chromosome gets moved to a non homologous chromosome

Question 24

Sex linked genes

Answer 24

Gene located on a sex chromosome (i.e. X-linked gene and Y-linked gene)

Have unique patterns (like expressing traits unrelated to sex; different from independent assortment)