Genetics: Final Review, Part 1

Front 1

prediction if homunculus hypothesis correct?

Back 1

all progeny will look like one parent

Front 2

prediction if blending hypothesis correct?

Back 2

all progeny will appear like mix of parents
recessive parental trait will not re-appear in F2

Front 3

alleles

Back 3

different copies of genes

Front 4

pure-breeding lines

Back 4

families of organisms that produce offspring with specific parental traits that remain constant from generation to generation

Front 5

segregation

Back 5

equal separation of alleles for each trait during gamete formation, in which one allele of each gene goes to each gamete

Front 6

mono-hybrid cross

Back 6

crosses between parents that differ in only one trait

Front 7

heterozygote

Back 7

individual with two different alleles for a given gene or locus

Front 8

homozygote

Back 8

individual with identical alleles for a given gene or locus

Front 9

test cross

Back 9

a cross used to determine the genotype of an individual showing a dominant phenotype by mating with an individual showing the recessive phenotype

Front 10

What is the genotype of a plant that produces yellow peas?

Back 10

Y/-

Front 11

What genotype can you cross with a Y/- plant with to help you
distinguish the correct genotype?

Back 11

y/y

Front 12

independent assortment

Back 12

alleles of one gene separate into gametes randomly with respect to alleles of other genes

Front 13

segregation

Back 13

the separation of the two alleles of a gene into different gametes

Front 14

Di-hybrid cross

Back 14

cross in which two traits are segregating

Front 15

Law of the product

Back 15

probability of 2 or more independent
events occurring together is the product of the probabilities
that each event will occur by itself.

Front 16

Law of the sum

Back 16

probability of two or more mutually
exclusive events occurring is the sum of their individual
probabilities

Front 17

What is the probability that the progeny of the R/r x R/r cross
will be wrinkled?

Back 17

probability that one parent will contribute r allele
X
probability that the other parent will contribute the r allele
1/2 X 1/2 = 1/4

Front 18

What is the probability that the progeny of the R/r x R/r cross
will be heterozygous?

Back 18

probability that one parent will contribute a dominant allele
X
probability that the other parent will contribute the recessive allele
(1/2 X 1/2) + (1/2 X1/2) = 2/4 = 1/2

Front 19

Affected children have at least one affected parent
Two affected parents can produce unaffected children,
if both parents are heterozygotes

Back 19

Dominant Traits: “Vertical” Pattern of Inheritance

Front 20

Affected children can be the children of two unaffected parents.
All of the children of two affected parents should be affected.

Back 20

Recessive traits: “Horizontal” patterns of inheritance

Front 21

If the recessive trait is common, the patterns of inheritance
may show a ______ pattern of inheritance (eg. sickle cell
anemia among African-Americans).

Back 21

If the recessive trait is common, the patterns of inheritance
may show a vertical pattern of inheritance (eg. sickle cell
anemia among African-Americans).

Front 22

A 1:2:1 ratio might imply:

Back 22

incomplete dominance
or
codominance

Front 23

Incomplete dominance

Back 23

phenotype of heterozygote is
intermediate between the phenotypes of the two homozygote
parents (often due to reduced gene dosage)

Front 24

Co-dominance

Back 24

phenotype of the heterozygote looks like
both homozygote parents

Front 25

haploinsufficicency

Back 25

a rare form of dominance in which an individual heterozygous for a wild=type allele and a null allele shows an abnormal phenotype because the level of gene activity is not enough to produce a normal phenotype

Front 26

null allele

Back 26

mutations that abolish the function of a protein encoded by the wild-type allele. Such mutations either prevent synthesis of the protein or promote synthesis of a protein incapable of carrying out any function