Introduction to Genetics: Meiosis

Introduction to Genetics: Meiosis

Introduction to Genetics: Meiosis CH. 11 ADAMS Pearson Prentice Hall Biology 11.1 The Work of Mendel Heredity: basically just the passing on of genetic traits from parents to offspring. Gregor Mendel: demonstrated that inheritance followed particular patterns

Every organism inherits a single copy of every gene from each of its parents. Offspring acquire genes from parents by inheriting chromosomes Pearson Prentice Hall Biology 11.1 The Work of Mendel Genes and Dominance Inheritance is possible because: Sperm and ova carrying each parents genes are combined in the nucleus of the fertilized egg True Breeding: (sometimes also called a purebred), is an

organism that always passes down certain physically expressed traits (purebred German Shepard) Hybrids: also known as cross breed, is the result of mixing, through sexual reproduction, two animals or plants of different breeds, varieties, species (German shepherd basset hound) Hybri d True Breed http://media.gettyimages.com/photos/germanshepherd-picture-id128603647?s=170667a http://www.nextdogbreed.com/ bhao/images/132.jpeg Pearson Prentice Hall Biology

11.1 The Work of Mendel Genes and Dominance Simplifying Genetics: So we've all got chromosomes, which are the form that our DNA takes in order to get passed on from parent to child. Human cells have 23 pairs of chromosomes Gene: a section of DNA in a specific location on a

chromosome that contains information that determines a trait. (hair color) Allele: specific gene, version of a gene (brown hair color) Pearson Prentice Hall Biology 11.1 The Work of Mendel Genes and Dominance Simplifying Genetics: So we've all got chromosomes, which are the form that our DNA takes in

Physical trait: a reflection of a bunch of different genes working together Pearson Prentice Hall Biology 11.1 The Work of Mendel Genes and Dominance Simplifying Genetics: Polygenic trait: are those traits that are controlled by more than one gene (hair color, eye color, height) Pleiotropic. : is single gene can influence how multiple traits

are going to be expressed Gamete is the male or female reproductive cell that contains half the genetic material of the organism. Pearson Prentice Hall Biology 11.1 The Work of Mendel Mendels 1st Two Conclusions: Conclusion: Biological inheritance is determined by

factor that are passed down from one generation to the next Factors are now called genes Each trait he studied was controlled by one gene in two forms producing different contrasting forms These different forms called alleles Pearson Prentice Hall Biology 11.1 The Work of Mendel Mendels

2nd Two Conclusions: Conclusion: Principle Of Dominance Some alleles are dominant and some are recessive Dominant traits will always show in offspring

Recessive only show when the dominant trait is not present Pearson Prentice Hall Biology 11.1 The Work of Mendel http://www.slideshare.net/guest9476bb/ib-biology-genetics-3807192 11.1 Segregation http://www.slideshare.net/guest9476bb/ib-biology-genetics-3807192 Pearson Prentice Hall Biology 11.1 Segregation

What happens to the recessive alleles? ~25% the recessive genes reappeared in Mendels experiments T-> dominant (TT; Tt) dominant trait will show (75%) T-> recessive (tt) only recessive trait will show (25%) Genotypes: 25% = TT 50% = Tt 25% = tt Pearson Prentice Hall Biology

11.2 Probability and Punnett Squares Mendel used the laws of probability to help predict results in plant succession Probability: how likely something is going to happen Relate to Genetics: Alleles segregation is random but the

laws of probability can be used to predict outcomes Pearson Prentice Hall Biology 11.2 Punnett Squares Drawings used to help predict genetic outcomes Below: Brown eyes are dominant (B); blue eyes are recessive (b). Both parents heterozygous for eye color Meaning that they carry the allele for both brown and blue

eyes This cross shows that 75% of the time offspring will have brown eyes but 25% they will have blue Phenotype: Brown eyes or blue eyes (phenotype is the physical characteristics) Genotype: 50% heterozygous 25% homozygous dominant 25% homozygous recessive http://study.com/cimages/multimages/16/Punnett_hetero_x_hetero.svg.png Pearson Prentice Hall Biology 11.2 Punnett Squares

Drawings used to help predict genetic outcomes Here we have one homologous recessive and one heterozygous W w w Ww Ww w ww ww

50% homozygous 50% heterozygous 50% dominant 50% recessive Pearson Prentice Hall Biology Drawings used to help predict genetic outcomes Below: Red flowers dominant(F); pink flowers recessive(f).

Both parents homozygous for petal color Meaning that they carry the allele for either red or white only This cross shows that 100% of the time offspring will have red petals but will be carriers for both Genotype: the genotype for this cross is Rr. The genetic make up (its the letters) http://dvbiology.org/biologyweb/pun2.gif The phenotype is red petals

Pearson Prentice Hall Biology 11.2 Punnett Squares Probability and segregation 25% of the time recessive genes that were segregated will reappear Probability and predict averages Higher your population of study the closer your averages are

Pearson Prentice Hall Biology Mendels Conclusions http://www.slideshare.net/guest9476bb/ib-biology-genetics-3807192 Pearson Prentice Hall Biology 11.3 Exploring Mendelian Genetics Independent Assortment Alleles can separate independently during the formation of gametes

Any one pair can combine with any other pair independently during construction This gives different traits equal opportunities to be expressed in offspring Pearson Prentice Hall Biology 11.3 Independent Assortment http://www.slideshare.net/guest9476bb/ib-biology-genetics-3807192 Pearson Prentice Hall Biology 11.3 Independent HOMOZYGOU

Assortment S HOMOZYGOU S TWO-FACTOR CROSS http://68.media.tumblr.com/18ac04cb50bf98a2362a93e8b02c685e/tumblr_inline_n92ctxcO5a1qg4nwx.png Pearson Prentice Hall Biology 11.3 Summary Mendel 1. Biological inheritance is determined by individual genes 2. In cases of two or more forms of the gene for a single trait

exist, some genes will exhibit over others 3. Dominance and recessive In most sexually reproducing organisms each offspring has two copies of a trait, one from each parent 4. In organisms that reproduce sexually, genes are passed from parent to offspring These traits can be segregated and reformed in new gametes Alleles for different genes will mostly segregate independently of one another

Pearson Prentice Hall Biology 11.3 Beyond Dominant and Recessive Mendel's Principles have two major exceptions Not all genes show simple patterns of dominant or recessive Many traits are controlled by one or more gene Majority

of genes have more than one allele Pearson Prentice Hall Biology 11.3 Incomplete Dominance Incomplete Dominance: intermediate inheritance where one allele for a specific trait is not entirely expressed over its paired allele. Results: in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.

http://www.biologia.arizona.edu/mendel/sets/mono/graphics/10TF1.gif Pearson Prentice Hall Biology 11.3 Codominance Codominance: Both alleles contribute to the phenotype. This results in offspring with a phenotype that is neither dominant nor recessive. http://cdn.shopify.com/s/files/1/0267/4223/products/codominance-panda-t-shirt-teeturtle_800x.jpg? v=1480438537 Pearson Prentice Hall Biology

11.3 Multiple Alleles Multiple Alleles Genes that have more than two alleles More than two possible alleles can exist https://ka-perseus-images.s3.amazonaws.com/d6049ca09dfc688504e47172cc9e692b04f3ca00.png Pearson Prentice Hall Biology 11.3 Polygenetic Other

examples: Fingerprints Eye color height http://www.slideshare.net/guest9476bb/ib-biology-genetics-3807192 Pearson Prentice Hall Biology 11.3 Polygenetic https://www.ontrack-media.net/biology/bm2l5rimage3.jpg Pearson Prentice Hall Biology 11.4 Meiosis Key terms:

Homologous Chromosome pairs: similar relation of chromosomes come from mom/other from dad Each of the chromosomes from dad have a corresponding pair from mom Diploid: meaning two sets of chromosomes (one inherited from each parent) Not

identical Haploid: meaning one set Pearson Prentice Hall Biology 11.4 Meiosis Chromosome Number The gametes (sex cells) haploid Meiosis: Somatic Not exact copies of parent

cells (body cells) are diploid Mitosis: Clones of parents Pearson Prentice Hall Biology Human Life Cycle Each human somatic cell (body cell) has 46 chromosomes or 23 matching pairs (diploid) Sex chromosomes: determine gender (XX; XY) Autosomes: non-sex chromosomes (somatic)

Pearson Prentice Hall Biology Review Chromosome: location of genetic information in the form of genes Chromatid: Each strand of a chromosome that divides longwise during cell division. Centromere: What connects the chromatids https://dr282zn36sxxg.cloudfront.net/datastreams/f-d %3A0cfa6ca6bdccc9a09f3ffe60c5e3d777529c14771d85ab4cc4f712b1%2BIMAGE_THUMB_POSTCARD_TINY %2BIMAGE_THUMB_POSTCARD_TINY.1

Pearson Prentice Hall Biology Phases of Meiosis Phases of Meiosis Mixture of chromosomes from both parental chromosomes Meiosis involves two divisions, meiosis I and meiosis II. By

the end of meiosis II, the diploid cell that entered meiosis has become 4 haploid cells. Pearson Prentice Hall Biology Phases of Meiosis I Major differences in Prophase I (meiosis) and Prophase (mitosis) Crossover http://pumatrendbio.weebly.com/uploads/6/0/9/7/60977291/398998105.png Pearson Prentice Hall Biology Interphase I Cells undergo a round of DNA replication, forming duplicate chromosomes.

Each chromosome pairs with its corresponding homologous chromosome to form a tetrad Tetrad is formed: structure of 4 chromatid Like Mitosis: cells undergo a round of DNA replication, forming duplicate chromosomes. http://www.phschool.com/science/biology_place/labbench/lab3/images/interpha.gif Pearson Prentice Hall Biology

Prophase I: Different from Mitosis Pairs of homologous chromosomes now will intertwine Crossover occurs Chromosomes swap genetic info http://pumatrendbio.weebly.com/uploads/6/0/9/7/60977291/398998105.png Pearson Prentice Hall Biology Cross Over When homologous chromosomes form tetrads in meiosis I, they exchange portions of their chromatids in a process called crossing over.

Crossing-over produces new combinations of alleles. Crossing-over occurs during meiosis. (1)Homologous chromosomes form a tetrad. (2)Chromatids cross over one another. (3)The crossed sections of the chromatids are exchanged. http://biologycellcycles.weebly.com/uploads/4/2/5/7/42572589/8819453_orig.jpg Pearson Prentice Hall Biology Metaphase I: Like Mitosis

Spindle fibers attach to the chromosomes. Chromosomes line up in the middle (just like mitosis) Pearson Prentice Hall Biology Anaphase I: Like Mitosis The fibers pull the homologous chromosomes toward opposite ends of the cell. Pearson Prentice Hall Biology Telophase I Nuclear

membrane reforms, Nucleoli form within Chromosomes unwind into chromatin Crease forms Pearson Prentice Hall Biology End of Round 1

We now have two haploid cells with 23 chromosomes each with unique combinations But we want to have 4 cells so we go for Round 2. Which is the same process but with different goal Instead of duplicating chromosomes we want to pull them apart into separate single strand chromosomes Unlike meiosis I, neither cell goes through chromosome replication.

Each of the cells chromosomes has 2 chromatids. Pearson Prentice Hall Biology Meiosis II During meiosis, the number of chromosomes per cell is cut in half through the separation of the homologous chromosomes. The result of meiosis is 4 haploid cells that are genetically different from one another and from the original cell. Prophase II Prophase II is where the nuclear membrane will again break down and the spindle fibers are formed. The chromosomes condense again after a interphase but this

time there is NO DNA replication http://www.utm.utoronto.ca/~w3bio380/picts/supp/supp2/Meiosis_ProphaseII.jpg Pearson Prentice Hall Biology Metaphase II The chromosomes line up in the center of cell. http://images.slideplayer.com/15/4802798/slides/slide_9.jpg Pearson Prentice Hall Biology Anaphase II The sister chromatids separate and move toward opposite ends of the cell.

http://images.slideplayer.com/15/4802798/slides/slide_10.jpg Pearson Prentice Hall Biology Telophase II Meiosis II results in four haploid (N) daughter cells. Cytokinesis when they finally separate http://keltonlesliealvarado.weebly.com/uploads/9/6/2/6/9626115/1652037.png Pearson Prentice Hall Biology Comparing Mitosis and Meiosis

Mitosis results in the production of two genetically identical diploid cells. Meiosis produces four genetically different haploid cells. Copyright Pearson Prentice Hall Comparing Mitosis and Meiosis Cells produced by mitosis have the same number of chromosomes and alleles as the original cell. Mitosis allows an organism to grow and replace cells.

Some organisms reproduce asexually by mitosis. NO change in number of chromosomes in daughter parent as parent cell. Copyright Pearson Prentice Hall Mitosis Meiosis Cells produced by meiosis have half the number of chromosomes as the parent

cell. These cells are genetically different from the diploid cell and from each other. Meiosis is how sexually-reproducing organisms produce gametes. Number of chromosomes are reduced to half of the number of the parent Copyright Pearson Prentice Hall Comparing Mitosis and

Meiosis Mitosis Exact copy Somatic cells Creates two cells One round of cell division Meiosis

Similar but not exact Gametes Creates 4 cells Two rounds of division Interphase I

Interphase Prophase I Prophase Metaphase I Metaphase

Anaphase I Anaphase Telophase/Cytokinesis I Telophase/Cytokinesis Interphase II

Prophase II Metaphase II Anaphase II Telophase/Cytokinesis II

Recently Viewed Presentations

  • There are two major classes of organic chemicals

    There are two major classes of organic chemicals

    Benzene is a planar molecule.The evidence suggests all the C-C bonds are the same and have a length and bond energy between a C-C single and C=C double bond The H-C-C bond angle is 120o in Benzene Theoretically because there...
  • MIT503 Veri Yapıları ve algoritmalar

    MIT503 Veri Yapıları ve algoritmalar

    Accordion - açılan kontainer kutularının sırası. Autocomplete - auto-complete giriş alanları. Button - yeni düğmeler. Datepicker - ileri tarih giriş alanı. Dialog - dialog kutuları. Menu - açılan menüler. Progressbar - progress bar aleti. Slider - slider aleti. Spinner -...
  • Second GradeOctober class news 2-6 Happy Birthday! No

    Second GradeOctober class news 2-6 Happy Birthday! No

    Spelling words: horse north forgot worm. Pork stork actor whale. when which bunch he's. I'll can't I'm we're. Vocabulary words. Gulp: to swallow loudly and suddenly
  • PATROLLING PART 1 - ArmyStudyGuide.com

    PATROLLING PART 1 - ArmyStudyGuide.com

    types: area reconnaissance zone reconnaissance raid ambush anti armor ambush security patrol conducted to obtain information concerning a specific location and the area immediately around it. the location of the objective is designated by either grid coordinates or a map...
  • Welcome to our Sunshine Community Epigenomics Meeting Concord,

    Welcome to our Sunshine Community Epigenomics Meeting Concord,

    Epigenomics - The Power to Create Your Own Genetic Destiny & introduction to NSP's new Thai Go Laurence Smith. NSP's new Sunshine Community. Greg Halladay. Questions and Answers . Tonight's . Agenda
  • ביטחון סייבר: סוגיות חמות הפרקליטות הצבאית 7.10.2014

    ביטחון סייבר: סוגיות חמות הפרקליטות הצבאית 7.10.2014

    a case-by-case basis. RULE 11. A . cyber operation constitutes a use of force when . its . scale . and effects . are comparable to non-cyber operations rising to the level of a use of force. (ICJ Nicaragua 1986)...
  • Leakage in MOS devices Mohammad Sharifkhani Reading  Text

    Leakage in MOS devices Mohammad Sharifkhani Reading Text

    GIDL is due to high field effect in the drain junction of an MOS transistor. Vg<0 Thins out the depletion region between drain to well PN junction. Effect of new electric field on the old PN depletion region holes tunnel...
  • Wetland Ecotone Just beyond this sign, you can

    Wetland Ecotone Just beyond this sign, you can

    Wetland Ecotone Just beyond this sign, you can clearly see the transition (or ecotone) between the upland ecosystem on the right and the wetland ecosystem on the left. The wetland ecosystem exists because frequent flooding and soil saturation reduces oxygen...