DAT Heredity cheat sheet

Question 1

A basic unit or sequence of genetic material
that encodes a trait

Answer 1

gene

Question 2

A gene’s location within a genome

Answer 2

locus

Question 3

Normal version of an allele

Answer 3

wild type

Question 4

A variant form of a gene

Answer 4

allele

Question 5

An allele with an altered DNA sequence
affecting a gene’s phenotype

Answer 5

mutant

Question 6

The alleles an individual carries (e.g., Aa)

Answer 6

genotype

Question 7

A pair of
chromosomes (1 maternal, 1 paternal) that
contain the same genes in the same locations

Answer 7

homologous chromosomes

Question 8

Having only one copy of a gene
instead of two

Answer 8

hemizygous

Question 9

Carrying a copy of the recessive
allele on one of the homologous chromosomes
and a copy of the dominant allele on the other
chromosome (e.g., Aa)

Answer 9

heterozygous

Question 10

Carrying the same alleles on each
homologous chromosome

Answer 10

homozygous

Question 11

pairs of alleles are separated when gametes are formed

Answer 11

segregation

Question 12

Pairs of alleles will be sorted
independently of one another
when gametes are formed

Answer 12

independent assortment

Question 13

One dominant allele masks
effect of recessive allele

Answer 13

principle of dominance

Question 14

gametes combine to form zygotes with two copies of each gene

Answer 14

fertilisation

Question 15

During anaphase I, homologous chromosomes segregate,
resulting in haploid gametes that
contain only one allele per gene

Answer 15

law of segregation

Question 16

The lining up & separation of one
pair of homologous chromosomes
does not influence that of a
different pair of homologous
chromosomes

Answer 16

the law of independent assortment

Question 17

A genetic cross between a homozygous recessive
individual and an individual in question to determine the latter’s
genotype for a given trait

Answer 17

test cross

Question 18

• Monohybrid cross tests

Answer 18

a single gene

Question 19

dihybrid cross tests

Answer 19

two
different genes
simultaneously

Question 20

P1

Answer 20

parental

Question 21

f1

Answer 21

first generation of offspring

Question 22

f2

Answer 22

second generation of offspring

Question 23

show all possible allelic
combinations of gametes in a cross between two individuals with known genotpyes

Answer 23

Punnett square

Question 24

One gene affects
the phenotypic expression
of an independently
inherited gene

Answer 24

epistasis

Question 25

More than two typical alleles exist for a gene

Answer 25

multiple alleles

Question 26

Many genes interact to shape a single phenotype, often with continuous variation (height)

Answer 26

polygenic inheritance

Question 27

Single gene controls for the expression of multiple phenotypic traits (e.g., a single gene controls a plant’s height, color, and texture)

Answer 27

Pleiotropy:

Question 28

There is a blending of alleles, producing a unique heterozygous phenotype

Answer 28

incomplete dominance

Question 29

both alleles are completely expressed

Answer 29

codominance

Question 30

reside on a sex chromosome

Answer 30

Sex-linked genes

Question 31

can be affected by the sex of the individual carrying the trait

Answer 31

sex influenced genes

Question 32

uses recombination frequency to show the relative positions of genes on a chromosome

Answer 32

linkage map

Question 33

The closer together the genes are, the less likely they are to be

Answer 33

separated by recombination

Question 34

reside close together on a chromosome,

Answer 34

linked genes

Question 35

During embryonic development in female mammals, one of the two X chromosomes is inactivated,

Answer 35

x-inactivation

Question 36

a highly condensed chromosome

Answer 36

barr body

Question 37

The proportion of individuals with a specific genotype will express the corresponding phenotype

Answer 37

penetrance

Question 38

The variation of a phenotype for a specific genotype

Answer 38

expressivity

Question 39

The occurrence of an abnormal number (extra/missing) of chromosomes

Answer 39

aneuploidy

Question 40

what often causes aneuploidy

Answer 40

nondisjunction

Question 41

Having three copies of chromosome 21 instead of the normal two copies

Answer 41

trisomy 21 (downs)

Question 42

The failure of chromosomes or chromatids to separate during Mitosis/Meiosis;

Answer 42

nondisjunction

Question 43

arrests mitosis by interfering with mitotic spindle formation;

Answer 43

Colchicine

Question 44

what can colchicine prevent cells from doing

Answer 44

replicating

Question 45

stimulate normal growth;

Answer 45

protooncogenes

Question 46

mutated protooncogenes can become what

Answer 46

oncogenes, cancer casuing

Question 47

make proteins that help control cell growth;

Answer 47

tumor suppressor genes

Question 48

A chromosome segment is rearranged in the reverse of its original orientation

Answer 48

inversion

Question 49

A chromosome segment is missing or deleted

Answer 49

deletion

Question 50

A chromosome segment is moved to another; it can be reciprocal or nonreciprocal (substitution)

Answer 50

trasnlocatin

Question 51

A chromosome segment is repeated on the same chromosome

Answer 51

duplication

Question 52

Changes in chromosome number or structure

Answer 52

Chromosomal aberrations:

Question 53

A single copy of the mutated gene is enough to express the condition

Answer 53

Autosomal dominant:

Question 54

Two copies of the mutated gene must be present to express the condition

Answer 54

autosomal recessive

Question 55

A single copy of the mutation of a gene on the X chromosome is enough to cause the condition in both males & females

Answer 55

X-linked dominant:

Question 56

Two copies of the mutated gene on the X chromosomes causes the condition in females; one copy will cause the condition in males

Answer 56

x linked recessive

Question 57

Genes located on the Y chromosome cause the condition/trait

Answer 57

y linked

Question 58

cannot be recessive

Answer 58

autosomal dominant

Question 59

cannot be dominant

Answer 59

autosomal recessive

Question 60

100% incidence of affected daughters from an affected father suggests

Answer 60

x linked dominance

Question 61

100% incidence of affected sons from an affected mother suggests

Answer 61

x linked recessive