Ch 12

Front 1

Character

Back 1

observable physical feature (e.g., flower color)

Front 2

Trait

Back 2

form of a character (e.g., purple flowers or white flowers)

Front 3

heritable trait

Back 3

is passed from parent to offspring

Front 4

true-breeding

Back 4

the observed trait is the only one present for many generations (inbreeding and selection)

Front 5

Mendel’s crosses

Back 5

Pollen from one parent was transferred to the stigma of the other parent.

Front 6

Mendel’s first experiment:

Back 6

Crossed plants differing in just one trait (P).
F1 generation are monohybrids.

Front 7

the particulate theory.

Back 7

Mendel proposed that the heritable units were discrete particles

Front 8

Diploid

Back 8

A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father. In a diploid state the haploid number is doubled, thus, this condition is also known as 2n.

Front 9

haploid.

Back 9

During gamete production, only one copy is given to the gamete

Front 10

Alleles

Back 10

Different forms of a gene

Front 11

homozygous

Back 11

have two copies of the same allele
(PP)

Front 12

Heterozygous

Back 12

have different alleles (Ss)

Front 13

Phenotype

Back 13

: Physical appearance of an organism (e.g., spherical seeds).

Front 14

Genotype

Back 14

: The genetic makeup (e.g., Ss).

Front 15

Mendel’s first law
The law of segregation

Back 15

The two copies of a gene separate when an individual makes gametes.

Front 16

Allele combinations can be predicted using a

Back 16

Punnett square

Front 17

Locus

Back 17

location on a chromosome of a gene

Front 18

a dihybrid cross.

Back 18

Crossing the F1 generation (all identical double heterozygotes) (SsYy)

Front 19

Mendel’s second law
The law of independent assortment:

Back 19

Alleles of different genes assort independently during gamete formation

Front 20

pedigrees

Back 20

Geneticists use pedigrees to determine whether a rare allele is dominant or recessive.

Front 21

mutation

Back 21

rare, stable, inherited changes in the genetic material

Front 22

Codominance:

Back 22

Two alleles at one locus produce phenotypes that are both present in the heterozygote.

Front 23

Pleiotropic.

Back 23

A single allele can have multiple phenotypic effects

Front 24

Epistasis:

Back 24

Phenotypic expression of one gene is influenced by another gene.

Front 25

Penetrance:

Back 25

Proportion of individuals with a certain genotype that show the phenotype

Front 26

Expressivity

Back 26

Degree to which genotype is expressed in an individual

Front 27

: Quantitative trait loci.

Back 27

Genes that determine these complex characters

Front 28

Absolute linkage is

Back 28

is rare
genes at different loci on the same chromosome do sometimes separate.

Front 29

Both sexes have two copies of all other chromosomes, called

Back 29

autosomes.

Front 30

- Turner syndrome.

Back 30

XO—the individual has only one sex chromosome

Front 31

XXY— Klinefelter syndrome

Back 31

affects males and results in sterility and overlong limbs.

Front 32

The SRY gene

Back 32

(sex-determining region on the Y chromosome) encodes a protein involved in primary sex determination