Transcript Genetics * Vocabulary Notes

Martin Sheen
How is it possible to maintain such genetic continuity?
Charlie Sheen
Kirk
Kirk Douglas
Michael
Emilio Estevez
Gregor Mendel’s
monastery garden.
Fig. 2.2
1
Removed stamens
from purple flower
2 Transferred sperm-
bearing pollen from
stamens of white
flower to eggbearing carpel of
purple flower
Parental
generation
(P)
3 Pollinated carpel
Stamens
Carpel (male)
(female)
matured into pod
4 Planted seeds
from pod
5 Examined
First
generation
offspring
(F1)
offspring:
all purple
flowers
EXPERIMENT True-breeding purple-flowered pea plants and
white-flowered pea plants were crossed (symbolized by ). The
resulting F1 hybrids were allowed to self-pollinate or were crosspollinated with other F1 hybrids. Flower color was then observed
in the F2 generation.
P Generation
(true-breeding
parents)

Purple
flowers
White
flowers
F1 Generation
(hybrids)
All plants had
purple flowers
RESULTS Both purple-flowered plants and whiteflowered plants appeared in the F2 generation. In Mendel’s
experiment, 705 plants had purple flowers, and 224 had white
flowers, a ratio of about 3 purple : 1 white.
F2 Generation
Phenotype
Purple
3
Purple
Genotype
PP
(homozygous)
1
Pp
(heterozygous)
2
Pp
(heterozygous)
Purple
1
Figure 14.6
White
pp
(homozygous)
Ratio 3:1
Ratio 1:2:1
1
White
(pp)
Purple
(Pp)
Gametes
p
Purple
(PP)
p
P
Gametes
Gametes
Purple
(Pp)
P
p
PP
Pp
P
Pp
Pp
Gametes
p
P
Pp
Pp
F1 generation
All purple
Pp
pp
F2 generation
¾ purple, ¼ white
Genotypes could be:
SS or Ss for stars
What would the genotype for no
stars have to be?
Parental P0 cross
P
P
p
p
F1 cross
P
p
P
p
Determine the genotype and phenotype
R
r
R
RR
Rr
r
Rr
rr
R
r
R
RR
Rr
R
RR
Rr