chapter 14 mendel and the gene idea. big idea 3: living systems store, retrieve, transmit and...
TRANSCRIPT
![Page 1: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/1.jpg)
CHAPTER 14Mendel and the Gene Idea
![Page 2: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/2.jpg)
Big Idea 3: Living systems store, retrieve, transmit and respond to
information essential to life processes.
• Mendel was able to describe a model of inheritance of traits, and his work represents an application of mathematical reasoning to a biological problem.
• However, most traits result from interactions of many genes and do not follow Mendelian patterns of inheritance (ex. hair color, eye color.)
• Understanding the genetic basis of specific phenotypes (physical outcomes due to proteins assembled) and their transmission in humans can raise social and ethical issues.
![Page 3: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/3.jpg)
What is INHERITANCE?
The study of how genes
and traits are passed from generation to generation.
![Page 4: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/4.jpg)
Genetic information provides for continuity of life and, in most cases,
this information is passed from parent to offspring via DNA.
Review meiosis w/ your partner.
1. What are the 3 sources of genetic variation for sexually reproducing organisms?
2. Why is it beneficial to be a “diploid” organism?
![Page 5: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/5.jpg)
1) Crossing over makes recombinant chromosomes that are unique.
• Independent assortment makes new combinations of chromosomes (one of each kind) in the gametes by “shuffling” the pairs of chromosomes.
• Fertilization joins gametes from two separate gene lineages (hopefully) to make a diploid zygote with new gene pairs.
2) Gene pairs = “back up copy” in case one gene is mutated/nonfunctional.
![Page 6: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/6.jpg)
GREGOR MENDEL:
The “father of genetics”
Austrian Monk
First to explain patterns of inheritance.
Analyzed sweet pea plantsover 12 years.
![Page 7: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/7.jpg)
Figure 14.x2 Round and wrinkled peas
Characteristic comesin 2 contrasting traits:Ex. PEA SHAPERound Wrinkled
Ex. FLOWER COLORPurpleWhite
![Page 8: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/8.jpg)
Mendel’s Experiments:Parent Generation (P generation):• Pure for one of two contrasting traits• Result of many generations of self-pollinationChose two plants pure for the two contrasting traits for
the characteristic flower color & crossed them.purple X white
![Page 9: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/9.jpg)
Mendel’s Experimental RESULTS:
(F1) First Generation :
• Offspring of parent generation
• All F1 plants looked like only one of the parents (that was the dominant trait)
• The recessive trait “disappeared”
• Hybrid offspring
![Page 10: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/10.jpg)
Table 14.1 The Results of Mendel’s F1 Crosses for Seven Characters in Pea Plants
![Page 11: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/11.jpg)
Mendel’s 2ndExperiment:
Mendel then crossed two F1 plants (“Ewww incest!” jk)
(F2) Second Filial Generation :
• The traits from both parents reappear in these offspring
Mendel found the ratio of expression to be 3:1
(3 dominant:1 recessive)
* note, not EXACTLY 3:1
![Page 12: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/12.jpg)
IMPORTANT CONCLUSIONS:
1. If a characteristic exists in two contrasting forms one is dominant, one is recessive.
2. Factors controlling traits occur in pairs.3. The dominant factor prevents the recessive factor
from being expressed.4. Recessive factors are only expressed when both
factors in the pair are recessive.5. When pea plants reproduce, a factor pair is
segregated (split) and each factor ends up in a separate gamete. Mendel’s law of segregation.
![Page 13: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/13.jpg)
In modern terms:1. Mendel’s factors are called
genes. Some genes are dominant, others recessive.
2. Different forms of a single gene are called alleles.
3. Genes occur in pairs, at the same position on two chromosomes.
4. The gene position is called the locus.
![Page 14: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/14.jpg)
5) The two chromosomes that contain the same genes are called: homologous.6) When solving inheritance problems, use capital letters to represent dominant
genes. T7) When solving inheritance problems, use lowercase letters to represent
recessive genes. t8) If both alleles in a gene pair are the same, we say the pair is: homozygous
(dominant or recessive) TT, tt9) If both alleles in a gene pair are different, we say the pair is: heterozygous. Tt10) A genotype is the combination of genes an individual possesses. (for one
trait shown w/ pair of letters) TT11) A phenotype is the appearance of an individual as the genes are being
expressed & proteins are being made or not made.
![Page 15: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/15.jpg)
![Page 16: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/16.jpg)
The Punnett Square• Used to solve inheritance problems• Predicts the possible gene combinations inherited by
the offspring• For example, a monohybrid cross: involves one
character/trait.ex. Heterozygous X Heterozygous (on board)
![Page 17: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/17.jpg)
Figure 14.8 Segregation of alleles and fertilization as chance events
POSSIBLE GENE COMBINATIONS FOR OFFSPRING ARE A RESULT OF 3 CHANCE EVENTS:1.Segregation of alleles into eggs2.Segregation of alleles into sperm3.Fertilization of WHICH egg by WHICH sperm
![Page 18: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/18.jpg)
Figure 14.4 Mendel’s law of segregation (Layer 2)
![Page 19: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/19.jpg)
Figure 14.6 A testcross
A test-cross: used to determine the genotype of an individual with a dominant phenotype…Not sure if they are Homo dom: PPOr Hetero: Pp
cross the individual in question with an individual with a recessive phenotype____ X homo rec
-> offspring phenotypeIf all dominant -> PPIf ½ recessive -> Pp
![Page 20: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/20.jpg)
For another example, a DIHYBRID cross: a two character/trait cross, with two gene pairs.
ex. AaBb X AaBb
(see board)
![Page 21: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/21.jpg)
Attractive, Boring X Attractive, Boring Man Woman
Both are Heterozygous for both genes…AaBb X AaBb
1. What gametes can each make?2. What are their chances of having: Attractive Boring kids? List the genotypes possible. #/16Attractive Exciting kids? List the genotypes possible. #/16Unattractive Boring kids? List the genotypes possible. #/16Unattractive Exciting kids? List the genotypes… #/16
![Page 22: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/22.jpg)
Mendel’s Law of Independent Assortment states when the two gene pairs are located on non-homologous chromosomes they segregate independently of each other. Results = 4 possible gamete combinations. (use FOIL) first: AB
outer: Ab inner: aB last: ab
![Page 23: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/23.jpg)
Attractive, Boring X Attractive, Boring Man Woman
Both are Heterozygous for both genes…AaBb X AaBb
• What gametes can each make? AB, Ab, aB, ab• What are their chances of having: Attractive Boring kids? List the genotypes possible. #/16AABB, AaBB, AaBb, AABbAttractive Exciting kids? List the genotypes possible. #/16Aabb, AAbbUnattractive Boring kids? List the genotypes possible. #/16aaBB, aaBbUnattractive Exciting kids? List the genotypes… #/16aabb
![Page 24: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/24.jpg)
AaBb X AaBb
![Page 25: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/25.jpg)
AaBb X AaBb
Ab abaBAB
Ab
aB
ab
AB
![Page 26: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/26.jpg)
AaBb X AaBb
AABB AABb AaBB AaBb
AABb AAbb AaBb Aabb
AaBB AaBb aaBB aaBb
AaBb Aabb aaBb aabb
Ab abaBAB
Ab
aB
ab
AB
![Page 27: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/27.jpg)
AaBb X AaBb
AABB AABb AaBB AaBb
AABb AAbb AaBb Aabb
AaBB AaBb aaBB aaBb
AaBb Aabb aaBb aabb
Ab abaBAB
Ab
aB
ab
AB
![Page 28: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/28.jpg)
Phenotype Ratio of dihybrid cross
9:3:3:19/16 Attractive, Boring3/16 Attractive, Exciting3/16 Unattractive, Boring1/16 Unattractive, Exciting
![Page 29: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/29.jpg)
Figure 14.7 Testing two hypotheses for segregation in a dihybrid cross
![Page 30: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/30.jpg)
Now, it can’t be that easy & boring can it?
No it can’t.
![Page 31: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/31.jpg)
1)Incomplete Dominance: Both alleles are the same strength
• Heterozygous individuals…express BOTH alleles, The resulting phenotype is a mix (blend) of the two.
• 3 phenotypes possible.• For example: Carnation
flower color• The alleles are also written
differently: AA’ or CR CW
CRCR CR CW CWCW
![Page 32: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/32.jpg)
2) Codominant Genes:• In a heterozygous individual
both alleles affect the phenotype in separate distinguishable ways.
• For example: Roan Horses have red (or black) and white hairs
• Another example: A, B, and AB blood groups in humans.
![Page 33: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/33.jpg)
3) Multiple Alleles: When more than
2 forms of the gene exist
• For example: Human Blood Types (ABO blood groups)• Blood cells have a carbohydrate marker that is found on the
surface of red blood cells.• These markers are called: A substance or B substance.• They are recognized by antibodies present in the blood serum
of individuals for foreign carbohydrate markers.• There are two types of RBC antibody: Anti-A & Anti-B• The genes for creating these antibodies are determined by the
genes for creating the A or B substance.
![Page 34: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/34.jpg)
Blood Type
Genotype Antigens on surface
of RBC
Plasma Antibodies
Donate Receive
A
B
AB
O
Write the possible genotypes for the blood types A, B, AB and O
![Page 35: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/35.jpg)
Blood Type
Genotype Antigens Plasma Antibodies
Donate Receive
A IA IA
IAi
B IB IB
IBi
AB IA IB
O ii
What are the actual antigens (surface molecules) found on the RBCs?
![Page 36: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/36.jpg)
Blood Type
Genotype Antigens on surface
Plasma Antibodies
Donate Receive
A IA IA
IAi
Substance A
B IB IB
IBi
Substance B
AB IA IB Substance
A and B
O ii none
What kinds of antibodies does Blood Type A make? Who can he/she Donate blood to? Receive it from?
![Page 37: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/37.jpg)
Blood Type
Genotype Substance on surface of
RBC
Plasma Antibodies
Donate Receive
A IA IA
IAi
Substance A
Anti-B Type A
& AB
Type A
& O
B IB IB
IBi
Substance B
AB IA IB AB
O ii none
Fill in the rest… check your work. Which kind are you? Which kindWhich is called the “universal donor”? The “universal recipient?”
![Page 38: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/38.jpg)
Blood Type
Genotype antigens Plasma Antibodies
Donate Receive
A IA IA
IAi
Substance A
Anti-B Type A
& AB
Type A
& O
B IB IB
IBi
Substance B
Anti-A Type B
& AB
Type B
& O
AB IA IB AB none TYPE
AB
A, B, AB & O
O ii none Anti-A
Anti-B
All blood types
Type O
Type AB is the universal recipient, Type O is the universal donor.
![Page 39: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/39.jpg)
Figure 14.10 Multiple alleles for the ABO blood groups
![Page 40: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/40.jpg)
Figure 14.10x ABO blood types
![Page 41: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/41.jpg)
• Remember, the IA & IB alleles are CODOMINANT.
• With human blood type, another marker called the Rh factor is denoted as + or -.
• So, type O -, is the worst to be in terms of getting a blood transfusion… but is the best donor.
• “universal donor”
![Page 42: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/42.jpg)
1) Pleiotropy: One gene influences many traits.
• (i.e. disease genes)• PKU (phenylketonuria). Mutation in a single gene
that codes for an enzyme results in: mental retardation, reduced hair, and skin pigmentation.
• Enzyme phenylalanine hydroxylase converts the amino acid phenylalanine to tyrosine.
• Absence of the enzyme causes phenylalanine to accumulate in toxic levels.
![Page 43: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/43.jpg)
Figure 14.15 Pleiotropic effects of the sickle-cell allele in a homozygote
![Page 44: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/44.jpg)
2) Epistasis: When two genes control the expression of a single trait. One gene pair
interferes with the expression of the other.
• Common for expression of pigment • For example: Fur color in mice. • Gene 1 = Fur color (B = Black fur, b = brown fur)• Gene 2 = Depositing pigment in the hair
(C = deposits color, c = deposits no color (albino))• What is the phenotypic ratio that results from the
cross a Black haired mouse, heterozygous both gene pairs and a Brown Haired mouse- heterozygous for gene 2?
![Page 45: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/45.jpg)
Figure 14.11 An example of epistasis
9:3:4
![Page 46: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/46.jpg)
3) Polygenic inheritance: When one phenotype is under the control of multiple gene pairs
• For example: Human Skin Color• Alleles are… Dark and light• At least… three genes control the color of your
skin• The phenotype is a result of… the cumulative
effects of the dominant genes• Human skin color exists… as a gradient
![Page 47: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/47.jpg)
Figure 14.12 A simplified model for polygenic inheritance of skin color
![Page 48: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/48.jpg)
![Page 49: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/49.jpg)
Figure 14.13 The effect of environment of phenotype
Multifactorial characters are influenced by genetics and environment.
Ph differences control the color of the hydrangeas.
![Page 50: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/50.jpg)
TAN=genes + Sun exposure / melanin production.
![Page 51: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/51.jpg)
"temperature sensitive" or ts mutants
Conditional mutants that grow at a low temperature but not at a high temperature are are called "temperature sensitive" or ts mutants.
Conditional mutants are not necessarily
associated with lethality.
The dark ear tips, nose and feet of a Siamese cat are the phenotype of a temperature sensitive mutation in the c locus (determining fur color).
The enzyme encoded is not functional at higher temperatures, but is functional at lower temperatures, such as the extremities of the cat.
Hence the fur on these parts of the Siamese cat’s body is pigmented.
![Page 52: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/52.jpg)
![Page 53: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/53.jpg)
PEDIGREE PROJECT (Complete over Thanksgiving)3 generationsExamples of TRUE mendelian traits (show dominance)WET EARWAX vs. dry earwax (recessive)PIGMENT vs. AlbinismRecessive: magenta urine after eating beats
![Page 54: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/54.jpg)
Pedigree• An analysis of the results of mating that
have already occurred- especially when studying a species with a long generation time.
• As much information as possible is collected about a family’s history for a particular trait.
• Information is assembled into a family tree describing the interrelationships across the generations.
• Helps us understand the past and predict the future.
![Page 55: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/55.jpg)
For those traits exhibiting dominant gene action:•affected individuals have at least one affected parent•the phenotype generally appears every generation•two unaffected parents only have unaffected offspring
And for those traits exhibiting recessive gene action:•unaffected parents can have affected offspring•affected progeny are both male and female
![Page 56: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/56.jpg)
Figure 14.16 Large families provide excellent case studies of human genetics
![Page 57: CHAPTER 14 Mendel and the Gene Idea. Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes. Mendel](https://reader033.vdocuments.mx/reader033/viewer/2022061305/5513e9ee55034674748b5894/html5/thumbnails/57.jpg)
Figure 14.17 Testing a fetus for genetic disorders