Title: pigment cell
1 pigment cell spotting
(S) silvering (Si) diminuation
(Dm) grizzling (Gr) pigment cell
development yellow (e) tortoiseshell
(eP) black (E) sootiness (so)
agouti (A) pigment yellow different
iation black color genes (C) dilution
(P) color modifiers (F)
pigment yellow brown black
guinea pig coat color pathway
B, b
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3early-flowering -- day 0 late-flowering ---
5 days later
P0 early x late F1 intermediate
(3.5 days later) F2 ¼ early ½
intermediate ¼ late
4complete (simple) dominance
0
1
0.5
aa
AA
Aa
incomplete dominance
0.5
0
1
aa
AA
Aa
codominance
0.5
1
0
aa
Aa
AA
5Dominance depends on the level of the phenotype
sickle cell anemia -- genetic disease HbA or
HbS
HbAHbA HbAHbS HbSHbS
normal normal severe anemia
Individual
normal sickle at sickle low O2
Cell
normal both sickle
Molecular
Individual HbA complete dominance Cell incompl
ete dominance Molecule codominance
6Drosophila Cy curly wing autosomal
Cy is dominant to wild type Cy/ flies have
curly wings
Cross curly x curly
expect all curly or ¾ curly, ¼
wild type observe 2/3 curly, 1/3 wild type
7Original cross must be between heterozygotes
i.e., curly x curly Cy/
Cy/ expect ¼ Cy/Cy ½ Cy/ ¼
/ vs. 2/3 curly 1/3 wild type
¾ curly ¼ wild type
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9 parents offspring
phenotypes Cross male female black sepia russ
et cream 1 black black 22 0 0
7 2 black russet 10 9 0
0 3 cream cream 0 0 11
34 4 sepia cream 0 24 11
12 5 black russet 13 0 0
12 6 black cream 19 20 0
0 7 black sepia 18 20 0
0 8 black sepia 14 8 6
0 9 sepia sepia 0 26 9 0
10 cream russet 0 0 15 0
10Self-incompatibility loci (S locus)
cross outcome pollen
ovule ( fertility) s1s2 s3s4
100 s1s3 s3s4 50 s3s4 s3s4
0
11multiple alleles and mixed dominance -- ABO blood
groups
phenotype genotype
O ii A IAIA or IAi
B IBIB or IBi AB IAIB
12eye color in Drosophila melanogaster
white x wild type wild type ,
white
wild type brick red apricot
yellow-orange cherry pink white white
and, apricot x cherry white
, apricot
13Complementation No Complementation
defective gene functional gene defective
gene functional gene
m1
m1
maternal chromosome paternal chromosome
G R
m2
m2
14complementation/noncomplementation of Drosophila
eye color
mutation white garnet ruby vermillion
cherry coral apricot buff
carnation white - -
- - - - garnet -
ruby -
vermillion -
cherry - - - - coral
- - - apricot - -
buff - carnation -
15wapricot
wcherry
wbuff
wcoral
w1
vermillion
carnation
white
garnet
ruby
1.5
7.5
44.4
0
33.0
62.5