Chap 17

Question 1

Probability

Answer 1

A study of outcomes

Question 2

Gregor Mendel

Answer 2

(1822-1884)

• demonstrated that heritable properties are divided in discrete units (genes) independently inherited
• used peas to “cross”

Question 3

Law of segregation

Answer 3

Each gene separates (after crossing over) during gamete formation ~meiosis~ so each gamete only has one copy

• each parent contributes 1 allele for each gene to their offspring
• males and females contribute equally to the traits in their offspring

Question 4

Selective breeding

Answer 4

A process in which people choose their breeding specific plants and animals for particular physical features or behaviours
Ex) wolf —-dog

Question 5

True breeding

Answer 5

(Mendel)
- he allowed plants to self pollinate to ensure that they were “true-breeding” (parental/P)
• exhibits the same characteristics gen after gen
~offspring: first filial (f1)/ second filial (f2)

Question 6

Mendel

Answer 6

Pollination and self pollination

Question 7

Monohybrid cross

Answer 7

One trait involved in this type of cross

-hybrid: offspring of a cross between 2 parent organisms traits

Question 8

Dominant

Answer 8

Mendel called these expressed characteristics dominant

-F1 generation

Question 9

Recessive

Answer 9

Characteristic that was not expressed

Question 10

Complete dominance

Answer 10

One form showed this over the other.
-An organism with one recessive and one dominant has same observable characteristics to an organism with two dominant forms

Question 11

Law of segregation

Answer 11

Mendel first law

• genes = factors
• gametes receive one copy of gene
• each organism have copies of each gene
• egg+sperm dude randomly
• one copy from each parent

Question 12

Genotype

Answer 12

Combination for alleles for any given trait (individual)

Question 13

Phenotype

Answer 13

Physical form of observable trait expressed

Question 14

Homozygous

Answer 14

An individual with 2 identical alleles for a trait

RR or rr

Question 15

Heterozygous

Answer 15

An individual with 2 different alleles for a trait

Rr

Question 16

Punnett square

Answer 16

A devised visual technique to analyse genotypes to determine the phenotypes

Question 17

Test cross

Answer 17

Is a cross between the organism of unknown genotype and a homozygous recessive organism
Ex) Walter nice

Question 18

Incomplete dominance

Answer 18

Describes a condition in which neither of two alleles for the same gene conceal presence of the other
-red&white flower= pink

Question 19

Co-dominance

Answer 19

Is a situation in which both alleles are fully expressed

Ex) roan horde (half and half)

Question 20

Dihybrid cross

Answer 20

Two genes involved in this type of cross

•opposite form of the same 2 traits

Question 21

Law of independent assortment

Answer 21

Mendels second law.

-two alleles for one gene segregate/assort independently of of the alleles for other genes during gamete formation

Question 22

Chromosome theory of inheritance

Answer 22

Walter Sutton published a paper proposing that genes are carried on chromosomes in 1902

Question 23

Linked genes

Answer 23

Genes are found on the same chromosome called linked genes

-assort on a regular basis through crossing over

Question 24

Crossing over

Answer 24

A random event that occurs with equal probability at nearly any point on a sister chromatid.
-more likely to occur between further appart genes than closer

Question 25

Chromosome mapping

Answer 25

Process called mapping

-the concept that crossing over is used to determine the relative positions of genes in a chromosome

Question 26

Map unit

Answer 26

Is defined distance between points on a chromosome where a crossover is likely to occur in 1% of all meiosis events
•map distance: distance between genes in a SINGLE Chromosome

Question 27

Recombinant types

Answer 27

Flies that have different combinations of alleles that the chromosome of the P generation are an example.
-recombinants= # of recombinant types/total# of offspring x100%

Question 28

Parental types

Answer 28

Flies that have chromosomes that are identical to those of the P generation

Question 29

Recombination frequency

Answer 29

Percentage of flies that are recombinant types correspond to recombination frequency
•the percentage of times that a crossover occurred as P gametes were formed

Question 30

Sex linked traits

Answer 30

Traits that are controlled by genes on either X or Y chromosome

Question 31

Barr Body

Answer 31

The inactive chromosome is condensed into a structure tightly. (Every female cell or 1 X chromosome = inactive)
~random: which X chromosome

Question 32

Multiple Alleles

Answer 32

A gene with more than two alleles

Ex) a clover (organism has 2+ alleles)

Question 33

Order of dominance

Answer 33

Sequence that can be written as
C > Cch>Ch>C
(> means dominant)

Question 34

Continuous traits

Answer 34

Traits for which the phenotype vary gradually from one extreme to another

• human height, ear length, corn

Question 35

Polygenic traits

Answer 35

Traits that are controlled by many genes.

-polygenic= a group of genes that contribute to same traits

Question 36

Gene mapping

Answer 36

The relative position of a he genes on the chromosome can be mapped using crossover frequency.
-drawing a map for given distanced between genes

Question 37

Pedigree

Answer 37

Human Genetics can follow the inheritance of numerous generations within a family to study patterns of inheritance
-Genetics use a diagram called a pedigree to show the patterns of relationships and traits in a family over gens

Question 38

Genetic Screening

Answer 38

the sequencing of human DNA in order to discover genetic differences, anomalies, or mutations that may prove pathological.

Question 39

Genetic counsellor

Answer 39

Genetic counselors work as members of a healthcare team, providing risk assessment, education and support to individuals and families at risk for, or diagnosed with, a variety of inherited conditions