Title: 1. In the first generation of each experiment, how do the characteristics of the offspring compare to the parents
1Section 11-1
- 1. In the first generation of each experiment,
how do the characteristics of the offspring
compare to the parents characteristics? - 2. How do the characteristics of the second
generation compare to the characteristics of the
first generation?
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2- Heredity The transmission of traits from parents
to offspring. - Who was Gregor ____________?
- Austrian monk and high school teacher born in
___________. - Father of _______________(1800s) study
of_______________ - Modern genetics is a core theme___________.
3Mendels data revealed patterns of inheritance.
- Mendel made ____________________in his
experiments. - use of ________plants
- control over __________observation of
seveneither-or traits
4- 4 stock plants
- Tall/Short Green/Yellow seeds
- The peas were self pollinating and producing an
exact copy of the parent plant. (True Breeding) - Mendel cross bred the seeds and got hybrid pea
plants. - How ? He took pollen from the male structures
(anthers) of a tall plant and placed it on the
female structures (pistil) of a short plant. - All of the offspring were hybrid tall (F1).
-
-
5A. Mendels Peas
- Chose garden peas to test.
- Why?
- Grow ___________________in very little space.
- True-breeding peas - all offspring show the same
______________after generation (homozygous). - Variety of _______________to study (tall v short,
white v purple, etc.) - Easy to ____________because closed flower doesnt
let random sperm/pollen in!
6- 4. Easy to control breeding
- male female parts are in a closed flower
other plant pollen cant get in. - a) self-pollinate fertilization in a single
plant using ________(sperm) and ____to make a
zygote (seed!)
7- Mendel wanted to study the results of breeding 2
different plants, so he had to prevent
self-pollination. - b) cross-pollination breeding ___________plants
8B.Mendels experiments
- Mendel studied__________________.
- What is a trait?
- A specific________________________.
- P Generation are the parent plants.
- F1 Generation are the 1st generation plants.
- F2 Generation are the 2nd generation plants.
- __________________and studied the results using
math. - Cant study them all at once
- Mendel studied _______________(1 variable) good
science!
9- Bred true breeding plants.
- True tall to true short.
- P ______________parents (homozygous)
- Tall x short
- b) F1 ____________(offspring of P,
heterozygous) - all tall
F2 second filial
P - parent
F1 first filial
102. Bred F1 x F1
- F2 ______________(offspring of F1)
- 3 tall1 short
F2 second filial
F1 first filial
P - parent
11- Mendels work led to 2 laws.
- _________________ Members of each pair of
alleles separate when the gametes are formed.
(Homologous Chromosomes separate) - ___________________ Pairs of alleles separate
independently of one another during gamete
formation.
12What do the results mean?
- _______________are passed unchanged as a unit
No blending! Genes DNA sequence on a
chromosome that codes for specific protein(s)
that determine traits (The ____________that
determine traits.) Alleles - different
expressions of same gene for same trait Ex one
allele codes for tall, one allele codes for short
but both the same ______________for height
13What do the results mean?
- _________________ during gamete formation,
alleles separate so you only inherit one copy of
each gene from each parent - F1 had to have both alleles to get a short plant
in F2, so the allele for shortness had to be
separated from the allele for tallness when
passed to the F2. - homologous chromosomes must separate
- When does this happen during sexual
reproduction???
MEIOSIS! Anaphase I
14What do the results mean?
- 3. ____________of Dominance one allele can mask
another allele. - Tall allele dominated short allele.
- ____________ allele or trait that is seen when
present, masks recessive allele. Capital letters
A - _____________ allele or trait that is only seen
if the dominant trait is NOT present. Lower case
letters a
15- Mendel drew three important conclusions.
- Traits are inherited as_________________.
- Organisms inherit_________________, one from each
parent. - The two copies_______during ________formation.
- The last two conclusions arecalled the law of
segregation.
16Interest Grabber continued
Section 11-2
1. Assuming that you expect 5 heads and 5 tails
in 10 tosses, how do the results of your tosses
compare? How about the results of your partners
tosses? How close was each set of results to what
was expected? 2. Add your results to those of
your partner to produce a total of 20 tosses.
Assuming that you expect 10 heads and 10 tails
in 20 tosses, how close are these results to what
was expected? 3. If you compiled the results for
the whole class, what results would you
expect? 4. How do the expected results differ
from the observed results?
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17Genes and Physical Traits
- __________ genetic makeup of alleles
- Geno genes
- Ex AA, Aa or aa dominant or recessive,
heterozygous or homozygous - _____________ physical expression of traits or
what organism looks like! - Pheno to show
- Ex tall or short, green or yellow, blue eyes or
brown eyes
18- What is homozygous?
- Having two identical alleles for a trait.
- Homozygous Dominant ________________ AA
- Homozygous Recessive ________________ aa
- What is heterozygous?
- Having _____________alleles for a trait. Aa
19The same gene can have many versions.
- A gene is a piece of DNA that directs a cell to
make a certain protein. - Each gene has a______, aspecific position on a
pair of___________chromosomes.
20- An allele is any _____________________occurring
at a specific locus on a chromosome.
- Each parent donates one allele for every gene.
- Homozygous describes two alleles that are the
same at a specific locus. - Heterozygous describes two alleles that are
different at a specific locus.
21- Alleles can be represented using letters.
- A dominant allele is expressed as a phenotype
when at least one allele is dominant. - A recessive allele is expressed as a phenotype
only when two copies are present. - Dominant alleles are represented by _________
letters recessive alleles by _______________
letters.
22- Both ________________________________ genotypes
yield a dominant phenotype.
- Most traits occur in a range and do not follow
simple dominant-recessive patterns.
23Probability and Punnet Squares
- Whenever Mendel crossed two hybrid plants (F1),
he got 31 ratio or ¾ dominant and ¼ recessive. - Mendel realized that the
- principles of probability
- (MATH!!) could be used
- to explain the_________
- _____________________
24Genetics and Probability
Probability - the likelihood that any particular
event(s) will occur
- Ex coin flip probability of heads is 1 chance
out of 2 possible outcomes 1/2, or 50. - Does heads on the first flip change the
probability of heads on the next? What if heads
10 times in a row will next flip be more likely
tails? - _____________do not affect future ones
25Genetics and Probability
- What is the probability that we will flip heads
three times in a row? - Because each event is independent
- (probability of event)N number of events
- or
- ½ x ½x ½ (½)3 1/8
- 1 in 8 chance that 3 heads flipped in a row
26Genetics and Probability
- How is this related to genetics?
- Allele segregation is ______________and each
event - ______________________
- _____________________a given allele from a
heterozygous parent 50 or 1/2 - If parent, T or t you have a 50 chance of
either, same as heads or tails
27Probability and Gender
- Females ________________
- What is the probability that you will inherit an
X from your mother? - Males __________________.
- What is the probability that you will inherit an
X from your dad? Probability of a Y? - What is the probability of having a boy? Having a
girl? - Which parents genes determine your gender?
- What is the probability that a family with three
children will have all girls? - (probability of event)N number of events
- ½ x ½x ½ (½)3 1/8
28- Why ________________squares?
- Predicts the probability of a cross between two
organisms. - Rules
- Dominant allele represented by a Capital
letter.______________ - Recessive allele represented by a lower case
letter _____________ - The letters designate the two forms of one gene,
the two alleles for a monohybrid cross. - Every cell in your body has at least two alleles
for every trait, one from Mom and one from Dad)
29Punnet Squares
- Punnett square grid showing possible gene
combinations for offspring from a given genetic
cross. - predicts ______________and their probability
- Shows phenotype __________________________
30Setting up a Punnett Square
- Determine _________genotype.
- _______for dominant, lower case__________.
- Top and left letters ____________________
- Bring down from top and over from left to create
possible ______________________for offspring.
Short plant x Tall heterozygote
Tt
Tt
tt
tt
31Ratios and Punnett Squares
- ________________ number of each type of
offspring genotype predicted by punnett square - For a single trait (_________________)
- homozygous dominant heterozygous homozygous
recessive - TT Tt tt
- ________________ number of each type of
offspring phenotype predicted by a punnett square - ____________________traits
- Tall short
32- Monohybrid Cross
- Provided data for one pair of contrasting traits.
- What are the possible genotypes that can result?
- What are the possible phenotypes that can result?
- What is the ratio of tall to short plants in a
hybrid cross? - Does this ratio agree with Mendels result in the
F2 generation?
33A monohybrid cross involves one trait.
- Monohybrid crosses examine ____________________
specific trait. - homozygous dominant-homozygous recessive all
heterozygous, all dominant
34- heterozygous-heterozygous___________________
dominant heterozygoushomozygous recessive 31
dominantrecessive
35- heterozygous-homozygous recessive11
heterozygoushomozygous recessive 11 - __________________________
- A testcross is a cross between an organism with
an unknown genotype and an organism with the
recessive phenotype.
36_____________________involves two traits.
- Mendels dihybrid crosses with heterozygous
plants yielded ________________phenotypic ratio.
- Mendels dihybrid crosses led to his second
law,the law of independent assortment. - The law of independent assortment states that
allele pairs separate independently of each other
during meiosis.
37Law of Independent Assortment
- genes for different traits can ___________________
_during the formation of gametes. - Independent assortment ____________________
- Mendel concluded that the inheritance of one
trait does not influence the inheritance of a
second trait
38Independent Assortment occurs in
__________________
39Heredity patterns can be calculated with
probability.
- Probability is the likelihood that something will
happen. - Probability predicts an average number of
occurrences, not an exact number of occurrences.
- Probability applies to random events such as
meiosis and fertilization.
40Probability and Punnett Square
- Probabilities predict averages,
- _____________
- outcomes
- Probability is more accurate when you have more
chances
41DIHYBRID CROSS
- Crossing organisms with genes for two different
traits _______________possible gametes. - If we cross RRYY with rryy what are the
possible gametes?
42- DIHYBRID CROSS punnett square for true breeding
or homozygous parents.
R round r wrinkled Y yellow y green
43 heterozygous
Offspring have combinations of alleles ________in
earlier generations ______________
independently
44DIHYBRID CROSS
- ___________________from dihybrid cross of
heterzygotes 9331
45Summary of Mendels Principles
- Traits come from your__________________.
- _____________________________allele and some are
dominant. - Your two copies of each gene (one from each
parent) are _________________when gametes form. - Alleles for different genes usually segregate
- __________________________of one another.
46Height in Humans
Section 11-3
Interest Grabber
- Height in pea plants is controlled by one of two
alleles the allele for a tall plant is the
dominant allele, while the allele for a short
plant is the ecessive one. What about people? Are
the factors that determine height more
complicated in humans?
Go to Section
47KEY CONCEPT Phenotype is affected by many
different factors.
48- Genetics can be affected by 5 other different
heredity patterns. - __________________Dominance
- ___________________
- _________ Traits (Multiple Genes)
- _____________ Influences
49Phenotype can depend on________________________.
- In incomplete dominance, neither allele is
completely dominant nor completely recessive. - Heterozygous phenotype is intermediate between
the two homozygous phenotypes - Homozygous parental phenotypes not seen in F1
offspring
501. Incomplete Dominance
neither allele is completely dominant
so _________________________
- cross between red-flowered (RR) and
white-flowered (WW) plants consists of
pink-colored flowers (RW). - What happens if you breed the pink flowers?
51- Codominant alleles will both be___________________
_.
- Codominant alleles are neither dominant nor
recessive. - The ABO blood types result from codominant
alleles.
- Many genes have more than______________________
522. Codominance
- both alleles expressed in the phenotype
____________________.
53- What are ____________ alleles?
- Genes that have more than two alleles for a
trait. Example ____ type in humans - What are ______________ traits?
- Traits that are controlled by two or more genes.
Example _______in humans.
543. Multiple Alleles
- Genes with more________________________
- This does not mean that an individual can have
more than two alleles. It only means that more
than two possible alleles exist in a population. - One of the best-known examples is blood type in
humans.
55Human Blood Types
- _______type alleles gene
- A makes A surface protein
- B makes B surface protein
- O doesnt make either.
- ____________alleles are codominant to each other
both __________over recessive O allele. - Is your blood type a genotype or phenotype?
564. Polygenic Traits
- Traits controlled by interaction of two or more
genes - _____________many genes.
- Ex Hair color, eye color, skin color all the
result of several genes
57- Environmental Influence
- Phenotype can depend on conditions in the
environment. - Conditions can cause a gene to _______
- __________________ in coat color.
- This allows the animal to blend in with its
background.
58ENVIRONMENT INFLUENCES ____________TRAITS
Environment factors like diet, exercise, exposure
to toxic agents, or medications can all influence
our genes and traits.
59Section 11-3
Concept Map
Gregor Mendel
concluded that
experimented with
which is called the
which is called the
Go to Section
60Linked Genes
- Mendel concluded that traits are assorted
independently, but some traits are Linked - Linked genes Genes usually _________________becau
se on same chromosome
61Sex-Linked Genes
- Genes on the sex chromosomes are linked.
- i. _________ genes Y has few genes mostly
gender determining (boy or girl). - Y only in males so these genes only affect males.
- ii. _______________ Many genes on X chromosome
- Affects mostly males because only________________
- Male copy of _____________(Dad gave Y to son)
- Females less affected because ______________
have to inherit trait from both parents. - Heterozygous females are _____________________trai
ts. - EX baldness, colorblindness
62Crossing Over affects linked genes.
- Crossing over exchanging DNA during prophase
- Genes _______on the chromosome _______ likely to
be separated by crossing over.
63Chromosome Mapping
- The farther apart genes are, the higher
probability that they will be separated by
crossing over. - Scientists conduct experiments to determine how
frequently genes of a particular trait are
separated from one another. - Chromosome map - _______________sequence of genes
on a chromosome. - Two genes that are separated by crossing-over 1
percent of the time are considered to be
one________________.
64Summary of Mendels Principles
- Traits come from your__________________.
- Genes may have ______________and some are
dominant. - Your two copies of each gene (one from each
parent) are ________________________when gametes
form. - Alleles for different genes usually
______________ - ________________ of one another.
65Beyond Mendel Other Patterns of Inheritance
- Most genes have more than two alleles.
- Some alleles are neither dominant nor recessive
(codominance incomplete dominance) - many traits are controlled by multiple genes.
- Some genes are linked and do not segregate
independently - on the same chromosome so
inherited together.