Talks about the transmission of genes beyond Gregor Mendel's concept of Inheritance

1. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
Objectives: Identify the different non-Mendelian Patterns of Inheritance
Explain how genes are being inherited
Explain how environment and genes influence one’s appearance and behaviour
Key Concept: Genes and Environment are the two factors that influenced the appearance and behavior of the
offspring.
Genetics is a field of biology that studies how traits are passed from parents to their offspring. The passing of traits
from parents to offspring is known as heredity, therefore, genetics is the study of heredity. Genetics is built around
molecules called DNA. DNA molecules hold all the genetic information for an organism. It provides cells with the
information they need to perform tasksthat allow an organism to grow, survive, and reproduce.Agene is one particular
section of a DNA molecule that tells a cell to perform one specific task.
Heredity is what makes children look like their parents. During reproduction, DNA is replicated and passed
from a parent to their offspring. This inheritance of genetic material by offspring influences the appearance and
behavior of the offspring. The environment that an organism lives in can also influence how genes are expressed.
Activity 1: Please define the following terms.
1. Genes - ___________________________________________________________________________________
2. Genotypic variation - _________________________________________________________________________
3. Phenotypic variation - ________________________________________________________________________
4. Recessive Trait - ____________________________________________________________________________
5. Dominant Trait - _____________________________________________________________________________
6. Sex-linked Inheritance - _______________________________________________________________________
7. Multiple Alleles (ABO Blood Group) - ____________________________________________________________
____________________________________________________________________________________________
8. Co-dominance - _____________________________________________________________________________
9. Incomplete Dominance - ______________________________________________________________________
10. Pedigree Chart - ___________________________________________________________________________
11. Autosomal - _______________________________________________________________________________
12. Heterozygous - ____________________________________________________________________________
13. Haploid - _________________________________________________________________________________
14. Diploid - __________________________________________________________________________________
Activity 2: Please read the article and answer the following questions.
The way that you carrya conversation, respond to failure,form relationshipswith others,and generallybehave
is in part related to your genetics - but your world and life experiences also shape your attitudes and behaviors. This
combination of your genetics and experiences ultimately forms your identity and influences your behavior.
Consider this example: Jennifer and Karen are identical twins. If both girls have geneticinformation (genes) associated
with obesity, does this mean that they will have no control over their weight? Or, if the girls are adopted by different
families and have different life experiences, will their environment dictate how much they will ultimately weigh?
Genes are instructions that dictate how a person's body is made, in the same way, that blueprints are
instructions to build a house. Information from genes lets the body know what characteristics a person will have, like
if they will have hairy or hairless ears and/or a small or big chin. These instructions come from our parents; when their
LESSON 1: The non-Mendelian Patterns of Inheritance
INTRODUCTION
ACTIVITY
How do genes influence who you are and what you do?

2. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
genesare mixed, our set of genesis formed. This is why we often look like a mixture of our parents! Ihave my mother's
blue eyes, but my father's stature. Almost everyone has different information in their genes, which makes sense given
how much diversity there is in how people look and act.
Cartoon showing how a son acquires eye color and height from parents.
Now consider the exception - identical twins. Identical twins look the same because each twin shares the same genes
as their identical sibling. Why? When a mother is pregnant, the fertilized egg holds the mixture of genes from both the
mother and father. Occasionally this fertilized egg splits into two eggs with the same mixture of genes. This results in
two identical people who are similar to one another in the way they look and behave.
Genes can carry instructions that can make it more likely for you to develop certain illnesses or conditions. For
example, Jennifer and Karen both have genes associated with obesity. Their genes could tell their body to:
increase the size of their fat cells or dictate how they use fat in their body
release chemicals (like hormones) which control hunger and appetite
influence behavior as Jennifer and Karen interactwith their environment.For example, if Karen begins
to gain weight, she may seek out fewer opportunities to exercise because going to the gym makes her
feel uncomfortable.
Suppose Jennifer is raised by wealthy parents who have access to the best, healthiest foods. Her parents
cook nutritious meals like vegetable risotto and lentil soup and limit the amount of sugar, salt, and fat their daughter
consumes. Jennifer learns to love fruits and vegetables and doesn't crave excessively salty or sweet foods. Her
parents have a significant amount of time to play with her and teach her to live an active lifestyle. By eating nutritious
foods and staying physically active, the genes increasing her chance of developing obesity are not expressed and
she never develops obesity.
Karen however is raised by low-income parentswho live in an area where fresh,healthy food is scarce and expensive.
Because her parents can’t afford fruits and vegetables, Karen eats a lot of frozen, packaged meals and fast food,
which are higher in sugar, fat, and salt. Her parents both work multiple jobs, and Karen spends her time alone in front
of the television. Karen’s eating and physical activity habits enhance the expression of her genes for obesity.
How do your life experiences influence your genes?

3. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
Flowchart of two twins demonstrating how their environment (the food they eat) influences their genetics which
determines whether they will be obese.
The characteristics (physical traits and behaviors) that you are born with and what you experience throughout
your life are both important. Your characteristics can impact your experiences and your experiences can impact your
characteristics. Karen and Jennifer’s life experiences influenced when and how their genes were expressed. The
relationship between your genes and behavior can change over time as you have new experiences. In some
situations, genes play a larger role in determining your behavior; in other situations, the environment plays a larger
role in influencing your behavior. If you had a whole different set of experiences over your lifetime your genes may be
expressed in different ways, and you may behave differently than you do now. If Jennifer and Karen had grown up in
the same environment, their health behaviors would probably be more similar to one another.
Scientists can look at the influence of genes on behavior by using a mathematical formula called a heritability
estimate. Heritability estimates give information about how much of an impact gene have on a behavior in a certain
environment. Think about blood type as an example - in your group of friends, there is probably some variation in your
blood types. If differences in blood type are mostly influenced by genes then the heritability estimate would reflect
that. Heritability estimates can range from 0 to 1; when the estimate is higher (closer to 1), this means that genes
have a larger influence on the behavior of interest, as it would be with blood type. When the estimate is lower (closer
to 0), it reflects a larger impact of the environment on the behavior. To study heritability, scientists use information
from identical twins that were separated at birth, like Karen and Jennifer. They do this because the genetic material
of identical twins is almost the same, which makes it easier to determine the relative influence of the environment.
Diagram showing blood type heritability from parents to children.
To better understand heritability estimates, consider Karen and Jennifer again. In Karen’s town where healthy
food is scarce - many of her neighbors do not get enough to eat and are malnourished. The athletic ability of Karen
and her neighbors is decreased and the heritability of athleticism is closer to 0 because their experiences in a
financially poor environment have inhibited genes associated with athleticism. On the other hand, Jennifer and her
neighbors eat plenty of healthy foods that are well-nourished. If we look at the athletic ability of Jennifer's neighbors,
the heritability estimate is closer to 1 because their experiences in a financially well off environment have enabled
their athleticism genes to be expressed.
A heritability estimate doesn’t tell us about a person’s chances for inheriting a certain genetic trait - Jennifer doesn’t
have a greater chance of being athletic because she lives in a well off the neighborhood. Heritability estimates give
Is there a way to tell how much of an influence gene have on behavior?

4. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
us more information about groups of people, like Jennifer and her neighbors. The varying levels of athleticism among
the people in her neighborhood can be explained by differences in their genetic makeup and differences in their life
experiences. When we calculate a heritability estimate, it gages how much of the differences can be explained by
each factor.
 Why do you think heritability estimates cannot be generalized or applied to different populations? Consider exactly
what a heritability estimate measures - the relative influence of genes and the environment. If there was a change in
the environment, the heritability estimate would change as well; an estimate from Jennifer's neighborhood would not
be applicable in Karen's neighborhood. Each estimate is very specific to one group of individuals and their
environment, which means that it could not be generalized. However, we can look at large groups of people and
develop a range of estimates to tell us more about a particular trait of interest. The range allows for interpersonal and
small group differences that are influenced by specific environments, but still gives us important information about the
differences in people's traits.
 The interactions between your genes and your environment are especially important during your early development.
For example, exposure to toxins during and immediately after pregnancy can produce lasting effects on a baby’s
health - children exposed to pesticides at a young age have a higher risk of developing mental health problems later
in life.
Process Questions:
1. Based on your physical appearance, where did you mostly inherit your characteristics, father, mother, or other
relatives? Based on your answer to the first question, what do you think is the reason why you inherit most of your
characteristics?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
2. How genes is being passed through to the offspring?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
3. What are the factors that contribute for the characteristics of an offspring?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
4. How genes, environment, personal experiences influence the characteristic of an offspring?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
Activity 3: Similar But Not Identical!
On your Laboratory Manual, answer pages 37-39. Read the instruction on pages 35-36. Take note, instead of
having the thumbprint of your classmate, ask the thumbprint of your family members or friends in the
community.
Consider the following:

5. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
Activity 4: Pedigree Analysis. Analyze the pedigree chart presented below and answer the following
questions.
Process Questions:
1. Based on the pedigree chart how many females are carrier of hemophilia disease and how many males are affected
of hemophilia disease?
____________________________________________________________________________________________
2. Is the trait recessive or dominant? Why?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
3. Is the trait sex-linked or autosomal? Why?
____________________________________________________________________________________________
____________________________________________________________________________________________
____________________________________________________________________________________________
Activity 5: Make a monohybrid cross of the following genes. Then identify the percentage of homozygous dominant,
homozygous recessive and heterozygous. Since there are only 4 boxes, therefore 100 percent is divided into four, so
each box is 25 percent.
In a monohybrid cross, we can apply the FOIL method (First, Outer, Inner, Last)
Example: LL x ll BB x Bbl l
L Ll Ll
L Ll Ll
B b
B BB Bb
B BB Bb
EXERCISES

6. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
If L – Large l – small If B – big b - small
Ll (Heterozygous - Large) – 100% BB (homozygous dominant-big) – 50%
Bb (heterozygous - small) – 50%
1. SS x ss
If S – Straight
S – curly
2. Ff x Ff
If F – Fat
F – thin
3. Tt x tt
If T – tall
t – short
Activity 6. Answer the following monohybrid cross based on the following conditions.
1. Incomplete Dominance
Rr x Rr If R – is red and r – is white What is/are the phenotype and
percentage of the offsprings?
____________________________
____________________________
2. Co-dominance
Bb x BB If B – is black and b – is white What is/are the phenotype and
percentage of the offsprings?
____________________________
____________________________
3. Multiple Alleles (ABO Blood Group)
Parent: ii x IAIB What are the blood type of the
offspring?
_________________________________
_________________________________
4. Sex-link inheritance
Parent: XYT x XX If: YT – webbed toes What is the percentage of affected
offspring?
What is the percentage of unaffected
offspring?
____________________________________
____________________________________
Activity 7: Marvels of Marbles: Predicting the Results of a Genetic Cross
On your LaboratoryManual answerpages 43-45.Read the instruction on pages 41-42.After,tearyour answers
on pages 43-45 then submit it together with your module.

7. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
Activity 8: My Pedigree, My Family Tree
On your LaboratoryManual answerpages 51-52.Read the instruction on pages 47-49.After,tearyour answers
on pages 43-45 then submit it together with your module.
TEST I: Multiple Choice. Encircle the letter that corresponds to the correct answer.
1. Haploid cells in human body _____________________.
a. contain 46 chromosomes
b. are caused by allelic variation
c. are typical examples of human cells
d. are gametes, which allow sexual reproduction
2. Hair color is determined bya single gene with a series of alleles,each resulting in different color.Hair color
is an example of __________________.
a. incomplete dominance c. polygenic trait
b. multiple allele d. sex-linked trait
3. The observed trait for white eyes in fruit flies is an example of a _____________ trait.
a. dominant c. sex-limited
b. polygenic d. sex-linked
4. Which of the following is a deviation from Mendelian principles?
a. Crossing-over occurs during meiosis.
b. Some forms of a gene may be dominant.
c. The inheritance of characteristics is determined by genes.
d. A gene can either mask or modify the phenotype controlled by another gene.
5. Which of the following statement is true about crossing-over?
a. It occurs only in males.
b. It occurs only in some chromosomes.
c. It results in genetic variation among gametes.
d. It occurs only between heterozygous genes.
For numbers 6 to 10, refer to the given situation.
Red-green color blindness is caused by an X-linked recessive allele. A color-blind (b) man marries a woman
with normal vision (B) whose father is color-blind.
6. What is the chance that the couple’s daughter will be color-blind?
a. 0% b. 25% c. 50 % d. 100%
7. What is the chance that the couple’s son will be color-blind?
a. 0% b. 25% c. 50 % d. 100%
8. What is the ratio of children with normal vision to those who will be color -blind?
a. 1:1 b. 3:1 c. 4:0 d. none of the above
9. What is the genotype of the father?
a. XbY b. XBY c.XBYb d. XbXB
10. What is the genotype of the mother?
a. XBXB b. XbXb c. XBXb d. XbXB
ASSESSMENT

8. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
For numbers 11 to 15, consider the experiment below.
Red-eyed fruit flies have the dominant trait (R), while white-eyed flies have the recessive trait (r). The recessive
allele Xr results in white-eyed males.
A cross was made between a heterozygous red-eyed female fruit fly and a white-eyed male fruit fly.
11. Out of the four offspring, how many will be red-eyed males?
a.0 b. 1 c. 2 d. 3
12. What will be the genotype of 50%of the female offspring?
a. XRXR b. XRXr c. XRY d. XrYr
13. What is the chance that the male offspring will be white -eyed?
a. 25% b. 50% c. 75% d. 100%
14. What is the chance that the female offspring will be white -eyed?
a. 25% b. 50% c. 75% d. 100%
15. What is the genotype of the female parent?
a. XRXR b. XrXr c. XRXr d. XrXR
TEST II. Restricted Response
1. “Bent”, a dominant sex-linked gene (C) in mice, results in a short, crooked tail. The recessive allele (c) produces
normal tails. If a normal-tailed female is mated to a bent-tailed mate, what phenotypic ratio will manifest in the F1,
generation?
2. Red-green color blindness is caused by an X-linked recessive allele. A color-blind man marries a woman with a
normal vision but whose father is color-blind. Will they have a colorblind daughter? Colorblind son? Explain your
answer?
3. A normal daughter of a man with hemophilia (a recessive sex-linked trait) marries a man who is normal for the trait.
What is the probability that their daughter will become hemophiliac? How about their son?

9. MODULE FOR SCIENCE 9
CHAPTER 2: Heredity and Variation
Learning Module in Science 9 - Ferlynsis H. Estrada
(to be filled up by the Teacher)
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Ferriols-Pavico J., Ramos A.C., Bayquen, A., Silverio A., Ramos, J.D, (2018) Exploring Life Through Science Series
Second Editio The New Grade 9
https://www.khanacademy.org/test-prep/mcat/behavior/behavior-and-genetics/a/genes-environment-and-behavior
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