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An Introduction to Genetics
Developmental Learning Style!
I “sensimotors” are
going to begin.
Lesson #1: Basic Genetics
• Keep track of your
answers.
• Good luck.
• Ready?
• NOTE: light blue
underlined text leads to a
Hyperlink. Click for more
information or the option
you desire.
Let’s ring the
bell to start.
General Background Information:
Genetics: study of how inheritable
characteristics are passed from one generation to
another.
 Genetic information (genes) are located in our
chromosomes. Chromosomes are made up of
deoxyribonucleic acid (DNA).
 DNA contains codes for organisms to make
PROTEINS, which are essential for the body to
function properly.
• Let’s start learning!
• Question: How many chromosomes do humans
have?
• A) 23
• B) 36
• C) 46
• D) 50
• Answer: C. Humans have 46 chromosomes. If
you were right, good job! If you were wrong,
don’t forget this number.
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Remember genes are located in ?
Chromosomes!
The genetic information is DNA.
How many chromosomes do we have?
46!
How many?
46
Genetics passes characteristics from
generation to generation.
• Characteristics describes an observable
feature that can appear in more than one
form.
• Trait is a variation of a characteristic.
• Soda Analogy:
• A soda drink is like a characteristic (type of
drink).
• A trait would be a variation of that
characteristic like Sprite, Coke, or Pepsi.
• Humans have different traits for the same
characteristic.
• For example, eye colour is a
characteristic.
• A trait for eye colour could be:
• Brown or blue etc.
• You may have even heard of a case of two
parents with brown eyes having a blue
eye child.
• Some other people, like actress Kate
Bosworth, have two different eye colours!
• Purebred: all the parents and offspring have
the same single TRAIT.
• Hybrid: when you mate two purebreeds with
different traits.
• Soda Analogy:
• Mix Coke with Coke = still a purebred Coke
• Mix Coke with Sprite = Swamp soda! A hybrid
• If parents with purebred brown eyes mate,
all their offspring would have?
• Brown eyes!
• How did Kate Bosworth get two different
eye colours?
• Maybe she got one trait from mom and
the other trait from dad.
•
(Note: Unfortunately, eye colour does not work that simply, but this example still shows the difference between
purebreeds and hybrids.)
We wonder what would happen if Kate
Bosworth and David Bowie had children?
• 1) What if you mated a purebreed purple
flower with a purebreed purple flower? What
colour would all of the offspring look like?
• A) Purple?
• B) White?
• C) Light Purple?
• The correct answer is PURPLE. Good for
you if you’re right! If not, you better start
paying closer attention.
• What would the characteristic be?
• Flower colour.
• What would the traits be?
• Purple OR White
• 2) What if you mated a purebreed white
flower with a purebreed white flower?
What colour would all of the offspring
look like?
• A) Purple?
• B) White?
• C) Light Purple?
• The correct answer is WHITE. That
should have been obvious.
• Characteristics are still flower colour.
• Traits are still purple OR white.
• 3) What if you mated a purebreed purple
flower with a purebreed white flower?
What colour would all of the offspring
look like?
• A) Purple?
• B) White?
• C) Light Purple?
• The correct answer is PURPLE. Huh?
Note the offspring is a HYBRID.
Make a selection before continuing:
• A If you think you have a good grasp on
the differences between
characteristics/traits/purebreed/hybrid,
good work and skip ahead.
• B If you have no idea what we are talking
about still, continue on with the tutorial.
• 1) What if you mated a purebreed tall plant
with a purebreed short plant? What the
offspring look like?
• A) Tall?
• B) Short?
• C) In between height?
• The correct answer is TALL.
• Characteristics?
• Height of the plant.
• Traits?
• Tall or short.
• 2) What if you mated a purebreed short
plant with a purebreed short plant? What
would the offspring look like?
• A) Tall?
• B) Short?
• C) In between height?
• The correct answer is SHORT. Great
work if you are getting all this so far!
• 3) What if you mated a purebreed tall
plant with a purebreed short plant? What
would the offspring look like?
• A) Tall?
• B) Short?
• C) In between?
• The answer is TALL. This offspring is a
HYBRID. Not getting it yet?
• Summary:
• The slides 4-16 use patterns of behaviorist
theories and developmental learning theories.
• Behaviourism: The exercise uses repetition
as a way for the learner to be exposed to the
material. Notice the straight-forward
acquisition of language. The terms were
presented in a list and in a repetitive manner.
• Piaget: Testing to see what would happen in
certain mating scenarios.
• Vygotsky & Bruner: Building on pre-existing
knowledge in the use of the soda analogy.
• The exercises were fairly simple and not
entirely interactive.
• We need some more definitions:
• A Trait can be DOMINANT or RECESSIVE
• Dominant: this is trait that appears even in
a hybrid.
• Recessive: the trait that is not expressed in
a hybrid. The trait is not visible if paired
with a dominant trait.
• Soda analogy:
• When mixing Coke with Sprite, Coke
dominates over Sprite in terms of colour.
• Brown eye colour is dominant over blue.
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•
•
•
We have already seen:
Purebred purple x purebred white = hybrid
All the hybrids are PURPLE.
Purple is dominant and it is the trait
expressed in a hybrid.
• WHITE trait is hidden, therefore it is
recessive.
• Soda Analogy:
• Mixing Coke with Sprite gives a lighter
coloured drink. This does not happen in
genetics. The Coke/Sprite hybrid would
look completely like Coke.
Make a selection before continuing:
• A If you think you have a good grasp on
the differences between dominant and
recessive, good work and skip ahead.
• B If you have no idea what we are talking
about still, continue on with the tutorial.
• Last set of questions: If brown eyes are a
dominant trait and blue eyes are a recessive
trait:
• The characteristics?
• Eye colour
• The traits?
• Brown or blue colour.
• The purebred dominant has:
• Brown eyes
• The purebred recessive has:
• Blue eyes
• The hybrid has:
• Brown eyes
Start of next lesson:
• Keep in mind what you have
learned thus far.
• Were you able to follow the
terms?
• Do you have a mastery of
basic genetic concepts?
• What were the deficiencies
of the previous lesson?
Time to get in
the “zone”.
Make a selection before continuing:
• A If you know your genetics, feel free to
skip ahead to try out some simple Punnett
square problems.
• B If you have no idea what we are talking
about, continue on with the tutorial.
• Genetics passes characteristics from
generation to generation. All organisms have
DNA information, which is needed for life.
• Question: Who gave us our genetic material?
• Answer: Your mother and father.
• If we have 46 chromosomes, how many
chromosomes did each of your parents give
you?
• 23 chromosomes from each parent for a total
of 46.
• That is the basis of sexual reproduction
(genetics style).
• Your genes come in pairs (one from mom and
one from dad).
• Each possible version of a gene is called an
ALLELE (fancy way of saying trait).
• For example:
• A purebred brown eyed mother has TWO
alleles for eye colour:
• One brown allele + one brown allele
• A dominant allele is written with a capital
letter like “B”.
• What if a father is purebred blue eyes?
• His two alleles are?
• A blue allele and a blue allele.
• We represent a recessive allele with a lower
case letter “b”.
• What happens when these parents mate?
• MATING OF TWO PUREBREEDS
• The mother has BB. The father has bb.
• Each parent can pass ONE allele (trait) and
every human needs TWO alleles to express a
specific trait.
• Mother can pass “B” or “B”.
• Father can pass “b” or “b”.
• That means a hybrid is formed:
Bb = brown eyes
A Punnett square is used in genetics to figure
out the probability of what the offspring will
look like.
• Use the following link to verify that two
purebreeds produce a hybrid
• Also note: The hybrid shows the DOMINANT
trait not the recessive one.
• Don’t worry about all the terminology on the
page.
• Just look at the squares Punnet square with
pea plants.
• Before we start predicting offspring and using
Punnett squares, we need to look at our last
terminology.
• If you notice you can have two types of
purebreeds: BB or bb
• The scientific words for purebreeds are:
• Homozygous DOMINANT = BB
• Homozygous RECESSIVE = bb
• For our hybrid (a mix of two alleles) = Bb
• Heterozygous = Bb = hybrid
• BB, Bb, bb = These letter combinations are
called GENOTYPES
• The genotypes tell us the PHysical
expressions which we call PHenotypes
• Soda Analogy:
• Coke is made up of chemicals (genotype)
that produce its taste and look (phenotype).
Trait
Genotype
Phenotype
Purebreed
Homozygous
dominant
Hybrid:
Heterozygous
BB
brown eyes
Bb
brown eyes
Note: two possible
alleles from this
parent: B or b
Purebreed:
Homozygous
recessive
bb
blue eyes
• Let’s try some practice questions:
• First read this website page, then click
“Practice Quiz” at the bottom of the page.
Let’s go a bit further:
• Try some of these problems on
your own.
• Review gametes (alleles)
• Try the Test Cross and
Monohybrid review (if you are
feel like you have mastery try the
DIHYBRID cross)
• This last link is OPTIONAL. It is a
difficult site with some terms you
haven’t seen, but it includes a
nice tutorial.
Socially I feel
good about
myself.
• Summary: Slides 18-33
• We purposely slowly phased out the
repetition (behaviorism).
• Piaget: There are small examples of the four
stages of development
• Sensorimotor skills: following the links and
points
• Preoperational: anticipating the results of the
mating
• Concrete: performing Punnett squares to see
probability
• Formal operations: The harder quizzes at the
end is asking you to develop new knowledge
• Vygotsky Summary:
• There was a need to develop the genetic
language in order to “play”.
• Play was developed using Punnett squares.
• Scaffolding was presented through the use of
the soda analogy.
• The more difficult genetics terminology raised
the learner into a zone of proximal
development.
• We purposely increased the level of difficulty
in the last portion of slides.
• The website links allowed for computer
interaction, but social collaboration is key part
missing through the exercise.
• Bruner Summary:
• By laying out the material in small categories
and building upon pre-existing knowledge
(the genetic terms presented earlier),
hopefully the learner was able to access the
more difficult genetic material.
• The use of analogy allowed to organize
information and compare existing schema.
• Seeing a real-life example (Kate Bosworth)
allowed integretion with previous knowledge
(scaffolding again).
• Quizzes were able to lead the viewer and
allow for correction.
• Questions:
• Did you have difficulty doing some of the
problems without knowing all of the language
that geneticists use, such as gametes,
Punnett square and F1 generation?
• What about the lack of connection of the
genetics concept with sexual reproduction
and meiosis? Did you find it difficult not
knowing why/how parents give one allele up?
• How would face to face interaction impact
your learning of genetic concepts?
References
Science Foundations 10, 2004 Edvantage
Press Lt., Victoria, British Columbia, Canada