Ch 15

Question 1

Thomas Hunt Morgan

Answer 1

20th century embryologist at Columbia whose evidence supported Mendelism and the chromosome

Question 2

What organism did Morgan choose?

Answer 2

fruit fly/ Drosophila

Question 3

What made the fruit fly vital to genetics?

Answer 3

Prolific mating
Only 4 chromosomes
eye color variant

Question 4

Morgan’s system of nomenclature

Answer 4

Symbol of mutant is the gene symbol and superscript + for wild type

Question 5

XY

Answer 5

male

Question 6

XX

Answer 6

female

Question 7

XO

Answer 7

XX for female XO for male

Ex: many insects

Question 8

ZW haplodiploidy

Answer 8

female = fertilized and diploid, male = unfertilized and haploid (no father)

Question 9

Inheritance of x-linked genes

Answer 9

Mothers pass an x to all offspring, 50% chance which one. Fathers pass the one x to all daughters only. For a recessive trait, female must be homozygous recessive and male must be hemizygous

Question 10

What happens when an organism has more than one of a sex chromosome?

Answer 10

inactivation

Question 11

Barr body

Answer 11

condensed form of an inactive x that lies along the inside of nuclear envelopes

Question 12

mosaicism

Answer 12

half of cells will express one X and half of cells will express the other. This allows for calico cats.

Question 13

Linked genes

Answer 13

located near each other so tend to be inherited together

Question 14

Linked genes break the law of…

Answer 14

independent assortment

Question 15

genetic recombination

Answer 15

production of offspring with combos of traits different from parents

Question 16

parental types

Answer 16

match either parent phenotype

Question 17

recombinants

Answer 17

new combos

Question 18

crossing over

Answer 18

recombines linked genes or genes on same chromosome

Question 19

genetic map

Answer 19

ordered list of genetic loci on chromsome

Question 20

linkage map

Answer 20

genetic map based on recombination frequencies

Question 21

map unit

Answer 21

1% recombination frequency

Question 22

max map units

Answer 22

50

Question 23

nondisjunction

Answer 23

failure of homologous chromosomes or sister chromatids to separate

Question 24

aneuploidy

Answer 24

abnormal number of a particular chromosome

Question 25

monosomic

Answer 25

one chromosome missing

Question 26

trisomic

Answer 26

one chromosome extra

Question 27

polyploidy

Answer 27

more than 2 full sets of chromosomes

Question 28

4n =

Answer 28

tetraploidy

Question 29

Polyploidy is common in plants because

Answer 29

it makes them larger and more robust

Question 30

What is Down syndrome?

Answer 30

trisomic for chromosome 21

Question 31

deletion

Answer 31

chromosomal fragment lost

Question 32

duplication

Answer 32

chromosomal fragment copied

Question 33

inversion

Answer 33

fragment reattached to original chromosome backwards

Question 34

translocation

Answer 34

fragment joins non homologous chromsomes

Question 35

reciprocal translocation

Answer 35

non homologous chromosomes switch fragments

Question 36

Klinefelter

Answer 36

XXY, sterile males

Question 37

XYY

Answer 37

aneuploidy that makes men typically taller

Question 38

Trisomy X/Triple X

Answer 38

XXX, taller females who are at risk for learning disabilities

Question 39

Turner Syndrome

Answer 39

XO, sterile female

Question 40

cri du chat chromosomal alteration

Answer 40

specific deletion of chromosome 5

Question 41

chronic myelogenous leukemia chromosomal alteration

Answer 41

exchange of a large part of chromosome 22 with a small part of chromosome 9 in white blood cells

Question 42

the CML alteration is an example of…

Answer 42

translocation

Question 43

Philadelphia chromosome

Answer 43

the new shortened chromosome 22 in CML

Question 44

genomic imprinting

Answer 44

variation on a phenotype depending on whether the allele is inherited from the male or female parent