CH9 camp Inheritance

Information about CH9 camp Inheritance

Published on December 14, 2007

Author: Alfanso

Source: authorstream.com

Content

CHAPTER 9:  CHAPTER 9 Patterns of Inheritance What is Inheritance?:  What is Inheritance? Passing on genetic information from parents to offspring Humans have 23 pairs of chromosomes (46 total) 1 of each pair is from one parent and the other is from the other parent Chromosomes:  Chromosomes Long strands of DNA that carry the genetic information on building and sustaining a living human being. Each chromosome contains many genes What is a Gene?:  What is a Gene? A segment of a chromosome that containing the code for a single protein (enzyme) - The enzyme causes a chemical reaction that allows a trait to be expressed. ie. Production of a pigment Alleles:  Alleles Alleles are alternate forms of a gene Homozygous individuals have two identical alleles for a trait Heterozygous individuals have two different alleles for a trait Gregor Mendel (1822 - 1884):  Gregor Mendel (1822 - 1884) Mendel was a monk who was trained in both biology and mathematics. He used his knowledge of biology to do test crosses on garden peas and count the progeny. He used his knowledge of mathematics to manipulate his data and derive his “postulates” for inheritance. In an Abbey Garden:  Mendel studied garden peas These plant are easily manipulated These plants can self-fertilize In an Abbey Garden Figure 9.5 Stamen Carpel Slide9:  Mendel carried out some cross-fertilizations Figure 9.6 Removed stamens from purple flower 1 2 3 Transferred pollen from stamens of white flower to carpel of purple flower 4 Planted seeds from pod Pollinated carpel matured into pod White Stamens Carpel Parents (P) Purple Offspring (F1) Slide10:  Mendel’s started with traits with homozygous alleles He called these true breeding plants Mendel’s plants showed simple dominance Presence of the dominant allele meant that the trait would be expressed whether homozygous or heterozygous For the recessive form of the trait, expression only occurs in the homozygous form Dominant alleles are shown as uppercase letters Recessive alleles are shown as lower case letters Mendel’s Principles of Segregation:  Mendel performed many experiments He tracked several characteristics in pea plants from which he formulated several hypotheses Mendel’s Principles of Segregation Slide12:  Figure 9.7 Dominant Recessive White Pod shape Inflated Constricted Flower position Pod Color Dominant Recessive Flower color Purple Axial Terminal Green Yellow Tall Dwarf Seed shape Round Wrinkled Seed color Yellow Green Stem length Monohybrid Crosses:  A monohybrid cross is a cross between parent plants that differ in only one characteristic Monohybrid Crosses Figure 9.8a P Generation (true-breeding parents) All plants have purple flowers Fertilization among F1 plants (F1  F1) F2 Generation 3/4 of plants have purple flowers 1/4 of plants have white flowers Purple flowers White flowers F1 Generation (a) Mendel’s crosses tracking one characteristic (flower color) Slide14:  Mendel developed four hypotheses from the monohybrid cross There are alternative forms of genes, now called alleles For each characteristic, each organism has two genes Gametes carry only one allele for each inherited characteristic Alleles can be dominant or recessive Slide15:  An explanation of Mendel’s results, including a Punnett square Wild type traits are those most often seen in nature:  Wild type traits are those most often seen in nature Selective breeding brings out selected alleles for a trait Slide18:  Phenotype An organism’s physical traits How does it look? Genotype An organism’s genetic makeup What alleles are present? Mendel’s principle of segregation:  Mendel’s principle of segregation Pairs of alleles segregate (separate) during gamete formation; the fusion of gametes at fertilization creates allele pairs again Mendel’s Principle of Independent Assortment:  Two hypotheses for gene assortment in a dihybrid cross Dependent assortment Independent assortment Mendel’s Principle of Independent Assortment Using a Testcross to Determine an Unknown Genotype:  Using a Testcross to Determine an Unknown Genotype A testcross is a mating between An individual of unknown genotype and A homozygous recessive individual Family Pedigrees:  Mendel’s principles apply to the inheritance of many human traits Family Pedigrees Figure 9.14 Freckles No freckles Widow’s peak Straight hairline Free earlobe Attached earlobe Slide24:  A family pedigree Shows the history of a trait in a family Allows researchers to analyze human traits Human Disorders Controlled by a Single Gene:  Many human traits Show simple inheritance patterns Are controlled by genes on autosomes Human Disorders Controlled by a Single Gene Slide26:  Table 9.1 Recessive Disorders:  Recessive Disorders Most human genetic disorders are recessive Individuals can be carriers of these diseases Dominant Disorders:  Some human genetic disorders are dominant Achondroplasia is a form of dwarfism Dominant Disorders Figure 9.17 BEYOND MENDEL:  Some patterns of genetic inheritance are not explained by Mendel’s principles Molecular genetics has provided some explanations BEYOND MENDEL Incomplete Dominance or Codominance:  Incomplete Dominance or Codominance In incomplete dominance F1 hybrids have an appearance in between the phenotypes of the two parents Slide31:  Hypercholesterolemia Is a human trait that is incompletely dominant Multiple Alleles and Blood Type:  The ABO blood groups in humans are examples of multiple alleles Possible alleles are A, B, or O Two of the human blood type alleles exhibit codominance Both alleles are expressed in the phenotype Multiple Alleles and Blood Type Figure 9.20 Pleiotropy:  Pleiotropy is the impact of a single gene on more than one characteristic Sickle-cell disease is an example Pleiotropy Slide35:  Figure 9.21 Individual homozygous for sickle-cell allele Sickle-cell (abnormal) hemoglobin Abnormal hemoglobin crystallizes, causing red blood cells to become sickle-shaped Sickled cells Breakdown of red blood cells Accumulation of sickled cells in spleen Physical weakness Anemia Heart failure Pain and fever Brain damage Damage to other organs Clumping of cells and clogging of small blood vessels Spleen damage Impaired mental function Paralysis Pneumonia and other infections Rheumatism Kidney failure Polygenic Inheritance:  Polygenic Inheritance Polygenic inheritance is the additive effects of two or more genes on a single phenotype The Role of Environment:  Many human characteristics result from a combination of heredity and environment The Role of Environment THE CHROMOSOMAL BASIS OF INHERITANCE:  THE CHROMOSOMAL BASIS OF INHERITANCE The chromosome theory of inheritance states that Genes are located on chromosomes The behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns Slide39:  Figure 9.23 P Generation Yellow-round seeds (YYRR) Meiosis Fertilization Gametes Green-wrinkled seeds (yyrr) F1 Generation Principle of Segregation: Follow the long chromosomes (carrying R and r) taking either the left or right branch. All round yellow seeds (RrYy) Principle of Independent Assortment: Follow both the long and the short chromosomes. The R and r alleles segregate in anaphase I of meiosis. Meiosis Metaphase I (alternative arrangements) They are arranged in either of two equally likely ways at metaphase I. Only one long chromosome ends up in each gamete. Metaphase II They assort independently, giving four gamete types. Gametes Fertilization recombines the r and R alleles at random. Fertilization among the F1 plants Fertilization results in the 9:3:3:1 phenotypic ratio in the F2 generation. F2 Generation Gene Linkage:  Gene Linkage In 1908, British biologists discovered an inheritance pattern inconsistent with Mendelian principles Slide41:  This inheritance pattern was later explained by linked genes, which are Genes located on the same chromosome Genes that are typically inherited together SEX CHROMOSOMES AND SEX-LINKED GENES:  SEX CHROMOSOMES AND SEX-LINKED GENES Sex chromosomes Influence the inheritance of certain traits Sex Determination in Human and Fruit Flies:  Sex Determination in Human and Fruit Flies Sex chromosomes Are designated X and Y Determine an individual’s sex Sex-Linked Genes:  Sex-linked genes Are any genes located on a sex chromosome Were discovered during studies on fruit flies Sex-Linked Genes Figure 9.28 (a) (b) Sex-Linked Disorders in Humans:  A number of human conditions result from sex-linked (X-linked) genes Sex-Linked Disorders in Humans Slide47:  Red-green color blindness Is a malfunction of light-sensitive cells in the eyes Figure 9.30 Slide48:  Hemophilia Is a blood-clotting disease Figure 9.31 Queen Victoria Albert Alice Louis Alexandra Czar Nicholas II of Russia Alexis BIOLOGY AND SOCIETY: TESTING YOUR BABY:  BIOLOGY AND SOCIETY: TESTING YOUR BABY Genetic testing Allows expectant parents to test for possibilities in their unborn child Includes amniocentesis and CVS Has risks associated with it Leads to Ethical Questions:  Leads to Ethical Questions If you knew that your fetus had Down’s Syndrome or some other genetic defect, would you end the pregnancy? If you wanted a boy but testing showed the fetus to be a girl????

Related presentations


Other presentations created by Alfanso

Chapter 1 Measurements
04. 01. 2008
0 views

Chapter 1 Measurements

webb
28. 09. 2007
0 views

webb

FSAFDY1
29. 09. 2007
0 views

FSAFDY1

Transgenic Wheat and Ethics
04. 10. 2007
0 views

Transgenic Wheat and Ethics

longitude
14. 11. 2007
0 views

longitude

ugbp5
21. 11. 2007
0 views

ugbp5

Ag Census 21 Slides Long Version
28. 12. 2007
0 views

Ag Census 21 Slides Long Version

tedc21
10. 12. 2007
0 views

tedc21

wkonept2
11. 12. 2007
0 views

wkonept2

osmopot
02. 01. 2008
0 views

osmopot

RoboticMilkEc
04. 01. 2008
0 views

RoboticMilkEc

2006 09 FortiMail Sales
07. 10. 2007
0 views

2006 09 FortiMail Sales

Domotica 2007 1 Introduzione
06. 11. 2007
0 views

Domotica 2007 1 Introduzione

JBrown MDSS sustainability
20. 11. 2007
0 views

JBrown MDSS sustainability

presentation 2q05
30. 11. 2007
0 views

presentation 2q05

enolagay
25. 12. 2007
0 views

enolagay

Planning a Healthy Diet chapte
06. 03. 2008
0 views

Planning a Healthy Diet chapte

Brian
26. 03. 2008
0 views

Brian

FPRE18 V AndyRobertson
07. 04. 2008
0 views

FPRE18 V AndyRobertson

b k ong
30. 03. 2008
0 views

b k ong

3a Stan Dorn
09. 04. 2008
0 views

3a Stan Dorn

ch15 CMBA 401
10. 04. 2008
0 views

ch15 CMBA 401

R Shant Feb US
13. 04. 2008
0 views

R Shant Feb US

Film Culture
19. 02. 2008
0 views

Film Culture

4 506
17. 04. 2008
0 views

4 506

SWAPS
22. 04. 2008
0 views

SWAPS

wroclawRoje
02. 11. 2007
0 views

wroclawRoje

veracruz
17. 06. 2007
0 views

veracruz

WordTalk PPT
17. 06. 2007
0 views

WordTalk PPT

Why IZS
17. 06. 2007
0 views

Why IZS

Why Use Oasis Pres from CR
17. 06. 2007
0 views

Why Use Oasis Pres from CR

W20 Levan Denenberg2
17. 06. 2007
0 views

W20 Levan Denenberg2

Voedsel allergie
17. 06. 2007
0 views

Voedsel allergie

Behind the spinning hourglass
03. 10. 2007
0 views

Behind the spinning hourglass

VIVA
17. 06. 2007
0 views

VIVA

PraatjestigmaAWF1002 2006
07. 01. 2008
0 views

PraatjestigmaAWF1002 2006

Stuttgart Presentation
16. 11. 2007
0 views

Stuttgart Presentation

coopres
28. 11. 2007
0 views

coopres

att2561
18. 03. 2008
0 views

att2561

BBonvillian
11. 10. 2007
0 views

BBonvillian

fullerton
22. 11. 2007
0 views

fullerton

VCCCD IT Tech Presentation
17. 06. 2007
0 views

VCCCD IT Tech Presentation