STRATEGIC INTERVENTION MATERIAL (S.I.M.) IN SCIENCE 9 Non-Mendelian Patterns of Inheritance: Codominance and Incomplete dominance Prepared by: ROMNICK O. SEGUIBAN
STRATEGIC
INTERVENTION MATERIAL
(S.I.M.) IN SCIENCE 9
Non-Mendelian
Patterns of Inheritance:
Codominance and
Incomplete dominance
Prepared by: ROMNICK O. SEGUIBAN
GUIDE CARD
TASK:
Explain and describe the characteristics of
codominance and incomplete dominance;
Find out the ratios or percentages of
identified genotype and phenotype
Use punnet square to show how an allele of
the parent affects their offspring
LEAST MASTERED SKILL:
Identifying the patterns of inheritance
Computing phenotypic and genotypic ratio of
non-mendelian genetics
OVERVIEW
In Grade 8, you learned that cells
divide to produce new cells and meiosis is one of
theprocesses producing genetic variations in
Mendelian patterns of inheritance. You will focus
on describing the location of genes in
chromosomes, explain the different patterns of
non- Mendelian inheritance and describe the
molecular structure of the DNA.
Gregor Mendel’s principles form the
base for the understanding of heredity and
variation. Although Mendel’s work failed to
discuss thoroughly the ‘factors’ or genes he
mentioned in his laws of inheritance, his findings
prompted other scientists to probe further into the
mystery of heredity. Several researches were
conducted after the rediscovery of Mendel’s work.
Mendelian laws of inheritance have
important exceptions to them. For example, not all
genes show simple patterns of dominant and
recessive alleles.
In incomplete dominance, a
heterozygote shows a phenotype that is
intermediate between the two homozygous
phenotypes. Neither allele is dominant over the
other.
Another pattern of inheritance is
codominance. This results when one allele is not
dominant over the other. The resulting
heterozygotes exhibit the traits of both parents.
ACTIVITY 1: “What pattern am I?
Identify if the following pictures exhibits CODOMINANCE
or INCOMPLETE DOMINANCE.
1.)
2.)
3.)
4.)
ACTIVITY 2: “FAIR & SQUARE”Use punnet square to predict their offspring based on
the type of inheritance.
1. Leaf color is controlled by
incomplete dominance. The allele
green leaf is “G” and “Y” for
yellow leaf. Both parents are
heterozygous.
2. Hair color is
controlled by
codominance. The
allele for blonde hair is
“B” and “G” for
grayish hair. The father
is a homozygous
blonde while the
mother is a
homozygous black hair.
ACTIVITY 3: “RA-TIO ME”Compute for the phenotypic ratio and
genotypic ratio of the following statements:
1. 2 pit bull dogs are homozygous and their skin color
is controlled by CODOMINANCE. The father has
dark skin while the mother has white skin.
2. A roan cow is a product of
codominance. What will be
the phenotypic ratio and
genotypic ratio if both parents
are roan cows?
3.The pattern of inheritance of black and white fur
of mice is controlled by incomplete dominance.
The father is a heterozygous and the mother is a
pure white.
ASSESSMENT CARD
Answer the following questions:
1.Explain the difference between incomplete dominance and
codominance:
2.In some chickens, the gene for feather color is controlled by
codominance. The allele for black is B and the allele for white is W. The
heterozygous phenotype is known as erminette.
a.What is the genotype for black chickens? ____
b.What is the genotype for white chickens? ____
c.What is the genotype for erminette chickens? ____
3.If two erminette chickens were crossed, what is the probability that:
a.They would have a black chick? ____%
b.They would have a white chick? ____%
4.In snapdragons, flower color is controlled by incomplete dominance. The
two alleles are red (R) and white (W). The heterozygous genotype is
expressed as pink.
a.What is the phenotype of a plant with the genotype RR? ___________
b.What is the phenotype of a plant with the genotype WW? ___________
c.What is the phenotype of a plant with the genotype RW? ___________
5.A pink-flowered plant is crossed with a white-flowered plant. What is the
probability of producing a pink-flowered plant? ____
ENRICHMENT CARD
REMEMBER THIS: If it is codominance BOTH alleles are expressed. If it
is incomplete dominance, alleles are MIXED or they BLEND when
expressed.
Go to youtube.com to
check out tons of related
videos about
codominance and
incomplete dominance. I
recommend this one for
you:
https://www.youtube.com/w
atch?v=YJHGfbW55l0
CHALLENGE:
a. If Gregor Mendel worked on
simple dominance, who discoved
incomplete dominance using four
o’ clocks?
b. What blood type exhibits
codominance?
ANSWER
CARD
ACTIVITY 1:
1. CODOMINANCE
2. INCOMPLETE DOMINANCE
3. CODOMINANCE
4. INCOMPLETE DOMINANCE
ACITIVITY 2:
1)
homozygous yellow leaf
homozygous green leaf
yellow green leaf
2.)
Blonde & grayish hair
Y G
Y YY YG
G YG GG
B B
G BG BG
G BG BG
ACTIVITY 3:
1) All or 100 % will have both skin color be expressed
1) 1 BB: 2BW: 1 WW
1 White cow: 2 Roan cows: 1 Brown
3) 1 BW: 1 WW
1 Gray fur: 1 pure white fur
ASSESSMENT:
1)INCOMPLETE DOMINANCE = ALLELES ARE MIXED/
BLEND; CODOMINANCE = BOTH ALLELES ARE
EXPRESSED
2)a. BB
b. WW
c. BW
3) a.25 %
b. 25%
4) a. RED FLOWER COLOR
b. WHITE FLOWER COLOR
c. PINK FLOWER COLOR
5) 50%
REFERENCE CARD
DEPED Learners’ Material Science9 Module 2 pp. 1-7
Modern Biology (Philippine Edition) pp.115 -127 by Velasquez,
C. & Asis, C.;
Concepts of Genetics pp 94 – 100 by Brooker, R.;
http://www.ck12.org/biology/Non-Mendelian-
Inheritance/lesson;
http://www.vcstulsa.org/faculty/Schenfield160/editoruploads/
files/genetics%20worksheet