Lesson Objectives Minds ON Yesterdays Recap Dominances and Blood Types Blood Typing Lab Success Criteria Homework Take Up New homework Minds ON Two rabbits are heterozygous Brown fur B is dominant to white fur b Dwarf small ears D are dominant to floppy ears d Draw a ID: 543193
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Dominance: Co-Dominance, Incomplete Dominance and Blood TypesSlide2
Lesson Objectives
Minds ONYesterday’s Recap Dominances and Blood Types
Blood Typing LabSuccess Criteria
Homework Take Up New homework Slide3
Minds ON
Two rabbits are heterozygous. Brown fur (B) is dominant to white fur (b). Dwarf (small) ears (D) are dominant to floppy ears (d). Draw a
Punnett square showing the possibilities.
We’ll do it together on the board once you’ve tried it. Slide4
Yesterday’s Recap
Dihybrid
CrossesRefers to the crossing of two individuals who are both heterozygous for TWO traits (e.g.
PpTt x PpTt)Assumes that these traits are on different genes and can occur at the same time.
E.g. Pod
colour
and seed
colourSlide5
Dihybrid Crosses
Parent 1 genotype is: AaBb
Parent 2 genotype is:
AaBbSlide6
Dominances
So far, we have been looking at situations where a dominant trait completely masks the allele
Bb/BB = dominant for purple colourSlide7
Incomplete Dominance
Occurs when:N
either gene is dominant or recessive
The gene effect is mixed We use 2 different letters for the homologous
pair since neither
is
dominant
.Slide8
An Example of Incomplete Dominance
With red and white snapdragons, the dominant allele that codes for the colour red is not completely dominant over the recessive allele that produces the white colour. The result is a pink flower. Slide9
Using a Punnett Square
Red Flower – RR White Flower
– WW
R = 100% Pink Offspring
x
W
W
R
RW
RW
R
RW
RWSlide10
Co-Dominance
Occurs when:Neither gene is dominant or recessive
Gene effects are NOT mixed
Therefore, both genes are expressed at the same time!Examples: Roan cow or Camelia
flower Slide11
An Example of Co-Dominance
Write C (for co-dominance) and a super script (R=Red,
W=white)Red haired = CRCR
White haired = CWCWRed and White (Roan) =CRCWSlide12
Using a Punnett Square
Red haired = CRCR
White haired = CWCW
Red and White (Roan) =CRCW = 100% Roan
X
XSlide13
Blood Types – A Special Case
There are three
alleles:
IA (Type A), IB (Type B) and i (Type O)A and B are co-dominant
O is recessive
+/- is the
Rh (Rhesus)
factor
(if
the Rh blood antigen is present, the person is Rh+; if not, they are
Rh-)
Predict offspring
bloodtypes
for:
Heterozygous type A mother, type O fatherSlide14
Using A Punnett
Square
X
i
i
i
ii
i
i
ii
X
i
i
ii
i
ii
IA (Type A), IB (Type B) and
i
(Type O)
-A
and B are co-dominant
-O
is recessive
50% = A
5-% = OSlide15
Blood Types
Types
Distribution
Ratios
O+
1 person in 3
38.4%
O-
1 person in 15
7.7%
A+
1 person in 3
32.3%
A-
1 person in 16
6.5%
B+
1 person in 12
9.4%
B-
1 person in 67
1.7%
AB+
1 person in 29
3.2%
AB-
1 person in 167
0.7%
AB universal plasma donors
AB+ universal recipients
O+ blood most needed
O- universal RBC donorSlide16
Rhesus Disease
An individual either has, or does not have, the "Rhesus factor" on the surface of their red blood cells.
The status is usually indicated by Rh positive (Rh+ does have the D antigen) or Rh negative (Rh− does not have the D antigen) suffix to the ABO blood type
.Rhesus Disease
occurs when there is incompatibility between blood types of mother and fetus.
Untreated, the result can cause death of the child.
Occurs in second and later
pregnanciesSlide17
Murder Mystery Lab
“I THINK THERE’S BEEN…(sunglasses on)..AN ACCIDENT!” (with emphasis)
https://www.youtube.com/watch?v=mznsEcZlM2I&noredirect=1
The Jim Carrey shows us…
https://
www.youtube.com/watch?v=HJSqkwyL1ZoSlide18
Lab
There’s been a murder. Hortatio
needs your help! You have to find out who did it. Agglutination:
refers to the clumping effect of blood when it is mixed with Anti-A , Anti-B or Rh serum . Go around to each station and sample the blood to find out the blood type and Rh factor to determine who killed One-Eyed Earl!