Fig. 9-1, p. 156
Jan 12, 2016
Fig. 9-1, p. 156
Fig. 9-2, p. 157
Genes occur in pairs on homologous chromosomes.
The members of each pair of genes may be identical in DNA
sequence, or they may be slightly different (alleles).
Fig. 9-3, p. 157
1
2
3
Fig. 9-4, p. 158
DNA replication DNA replication
meiosis I meiosis I
meiosis II meiosis II
(gametes) (gametes)
(zygote)
Fig. 9-4, p. 158
DNA replication DNA replication
meiosis I meiosis I
meiosis II meiosis II
(gametes) (gametes)
(zygote)Stepped Art
Fig. 9-5, p. 159
Fig. 9-5a, p. 159
female gametes
mal
e g
amet
es
A Making a Punnett square. The possible parental gametes are listed on the top and left sides of the grid (in circles). Each square is filled in with the combination of alleles that would result if the gametes in the corresponding row and column met up.
Fig. 9-5b, p. 159
offspring
Heterozygous parent
Heterozygous parent
B A Punnett square shows that the ratio of dominant-to-recessive phenotypes among offspring of a monohybrid cross is about 3:1 (3 purple to 1 white).
Fig. 9-5b, p. 159
offspring
Heterozygous parent
Heterozygous parent
B) A Punnett square shows that the ratio of dominant-to-recessive phenotypes among offspring of a monohybrid cross is about 3:1 (3 purple to 1 white).
Stepped Art
female gametes
mal
e g
amet
es
A) Making a Punnett square. The possible parental gametes are listed on the top and left sides of the grid (in circles). Each square is filled in with the combination of alleles that would result if the gametes in the corresponding row and column met up.
Fig. 9-6, p. 160
C) Two nuclei form with each scenario, so there are a total of four possible combinations of parental chromosomes in the nuclei that form after meiosis I.
meiosis I meiosis I
D) Thus, when sister chromatids separate during meiosis II, the gametes that result have one of four possible combinations of maternal and paternal chromosomes.
meiosis II meiosis II
gamete genotype:
A) This example shows just two pairs of homologous chromosomes in the nucleus of a diploid (2n) reproductive cell. Maternal and paternal chromosomes, shown in pink and blue, have already been duplicated.
B) Either chromosome of a pair may get attached to either spindle pole during meiosis I. With two pairs of homologous chromosomes, there are two different ways that the maternal and paternal homologues can get attached to opposite spindle poles.
or
Stepped Art
Fig. 9-7, p. 161
Fig. 9-7a, p. 161
parent plant homozygous
for purple flowers and long stems
parent plant homozygous
for white flowers and short stems
dihybrid
four types of gametes
Fig. 9-7b, p. 161
Fig. 9-7b, p. 161
Stepped Art
parent plant homozygous
for purple flowers and long stems
parent plant homozygous
for white flowers and short stems
2) dihybrid
3) four types of gametes
Fig. 9-8, p. 162
Fig. 9-9, p. 163
Genotypes:
Phenotypes (blood type): A AB B O
Fig. 9-10a, p. 163
homozygous parent (RR)
x homozygous parent (rr)
heterozygous offspring (Rr)
A Cross a red-flowered with a white-flowered plant, and all of the offspring will be pink heterozygotes.
Fig. 9-10b, p. 163
B If two of the heterozygotes are crossed, the phenotypes of the resulting offspring will occur in a 1:2:1 ratio.
Fig. 9-11, p. 164
Fig. 9-12, p. 165
Fig. 9-12a, p. 165
Fig. 9-12b, p. 165
Fig. 9-14, p. 166
60 60 60
Hei
gh
t (c
enti
met
ers)
0 0 0
A Plant grown at high elevation (3,060 meters above sea level)
B Plant grown at mid-elevation (1,400 meters above sea level)
C Plant grown at low elevation (30 meters above sea level)
marriage/mating
female
male
offspring
individual showing trait being studiedsex not specifiedgeneration
A) Standard symbols used in pedigrees
B) A pedigree for polydactyly, which is characterized by extra fingers, toes, or both. The black numbers signify the number of fingers on each hand; the blue numbers signify the number of toes on each foot.
Fig. 9-15, p. 167
*Gene not expressed in this carrier.
Stepped Art
Table 9-1, p. 168
Fig. 9-16a, p. 168
normal mother
affected father
meiosis and gamete formation
affected child
normal child
disorder-causing allele (dominant)
Fig. 9-16b, p. 168
Fig. 9-17, p. 169
Fig. 9-17a, p. 169
carrier mother carrier father
meiosis and gamete formation
affected child
carrier child
normal childdisorder-causing allele (recessive)
Table 9-2, p. 169
Table 9-3, p. 170
Fig. 9-18 (top), p. 170
Fig. 9-18 (a-d), p. 170
Fig. 9-19, p. 171
Table 9-4, p. 171
Fig. 9-20a, p. 172
Metaphase I Anaphase I Telophase I Metaphase II Anaphase II Telophase II
Fig. 9-20b, p. 172
Fig. 9-20b, p. 172
Stepped Art
Metaphase I Anaphase I Telophase I Metaphase II Anaphase II Telophase II
Fig. 9-20c, p. 172
p. 174
Fig. 9-23, p. 175
Fig. 9-24, p. 177