Ppt on chromosomes and genes and alleles

Variation: alleles & mutations. Genotype, phenotype & crosses.

another. Please note that each sex cell contains 50% of the original gene. Ee = gene of the Hybrid parent. Principle of Independent Assortment Independent assortment occurs because in meiosis the segregation of one pair of homologous chromosomes (and the alleles they carry) does not influence the segregation of other homologous pairs of chromosomes A ratio of 9:3:3:1 will be observed if the following/


DNA in a Normal Cell (one chromosome from each parent) Allele Allele  A version of a gene Dominant Dominant  Allele that may mask the presence of another.

chromosome from each parent) Allele Allele  A version of a gene Dominant Dominant  Allele that may mask the presence of another Recessive Recessive  Allele that may be masked by another Heterozygous Heterozygous  The 2 alleles are different Homozygous Homozygous  The 2 alleles are identical Earlobe Gene Toe Gene Polydactyly Gene FFreefAttached tLong big toe tLong PExtraFingersPExtraFingers ♂♀ DNA in a Normal Cell (one chromosome/ of mucus in the lungs, liver, and pancreas. If two healthy people have a/


Overview: Locating Genes Along Chromosomes

b vg vg b b vg vg b b vg vg PREDICTED RATIOS If genes are located on different chromosomes: 1 : 1 : 1 : 1 If genes are located on the same chromosome and parental alleles are always inherited together: 1 : 1 : : RESULTS 965 : 944 : 206 : 185 b+ vg+ b vg F1 dihybrid female and homozygous recessive male in testcross b vg b vg b+ vg+ b vg/


The Chromosomal Basis of Inheritance

Mendel’s laws Law of segregation: Two alleles for each gene segregate during gamete formation and end up in different gametes  Each gamete gets only one of the two alleles  In terms of chromosomes, this segregation corresponds to the distribution of homologous chromosomes to different gamete (R or r allele; Y or y allele) Law of independent assortment: Alleles of genes on nonhomologous chromosomes assort independently during gamete formation  Each gamete/


Inheritance, Genes, and Chromosomes 8. Chapter 8 Inheritance, Genes, and Chromosomes Key Concepts 8.1 Genes Are Particulate and Are Inherited According.

Inheritance, Genes, and Chromosomes 8 Chapter 8 Inheritance, Genes, and Chromosomes Key Concepts 8.1 Genes Are Particulate and Are Inherited According to Mendel’s Laws 8.2 Alleles and Genes Interact to Produce Phenotypes 8.3 Genes Are Carried on Chromosomes 8.4 Prokaryotes Can Exchange Genetic Material Chapter 8 Opening Question How is hemophilia inherited through the mother, and why is it more frequent in males? Concept 8.1 Genes Are Particulate and Are Inherited/


Genes, Chromosomes, and Human Genetics

+ = red eyes pr = purple + = normal wings vg = vestigial wings Genetic Recombination Alleles linked on same chromosome exchange segments between homologous chromosomes Exchanges occur while homologous chromosomes pair during prophase I of meiosis Evidence for Gene Linkage Linked genes Genes that are close together on the same chromosome Belong to the same linkage group Linkage and Recombination Linkage; genes are inherited together Crossing over produces recombination – breaks up the association of/


GENETICS & EVOLUtion: chromosomal inheritance & mutation

b vg+ vg PREDICTED RATIOS If genes are located on different chromosomes: 1 : 1 : 1 : 1 If genes are located on the same chromosome and parental alleles are always inherited together: 1 : 1 : : RESULTS 965 : 944 : 206 : 185 Genetic Recombination and Linkage The genetic findings of Mendel and Morgan relate to the chromosomal basis of recombination Recombination of Unlinked Genes: Independent Assortment of Chromosomes Mendel observed that combinations of traits in/


Overview: Locating Genes Along Chromosomes

b b vg vg b b vg vg b b vg vg PREDICTED RATIOS If genes are located on different chromosomes: 1 : 1 : 1 : 1 If genes are located on the same chromosome and parental alleles are always inherited together: 1 : 1 : : RESULTS 965 : 944 : 206 : 185 Morgan found that body color and wing size are usually inherited together in specific combinations (parental phenotypes) He noted that/


10 Genetics: Mendel and Beyond. 10.1 What Are the Mendelian Laws of Inheritance? People have been cross-breeding plants and animals for at least 5,000.

linked. All the loci on a chromosome form a linkage group. 10.2 How Do Alleles Interact? Different alleles arise through mutation: rare, stable, inherited changes in the genetic material. Wild type: allele present in most of the population. Other alleles are mutant alleles. Genes associated with the X and Y chromosomes are said to be sex-linked. 10.3 How Do Genes Interact? Genes that determine these complex characters: quantitative/


Locating Genes Along Chromosomes

A c b a P generation gametes D E d e + F f The alleles of unlinked genes are either on separate chromosomes (such as d and e) or so far apart on the same chromosome (c and f ) that they assort independently. This F1 cell has 2n = 6 chromosomes and is heterozygous for all six genes shown (AaBbCcDdEeFf ). Red = maternal; blue = paternal. D e C B d Each/


Genes Are located on chromosomes

with two true-breeding pea plants, we follow two genes through the F1 and F2 generations. The two genes specify seed color (allele Y for yellow and allele y for green) and seed shape (allele R for round and allele r for wrinkled). These two genes are on different chromosomes. (Peas have seven chromosome pairs, but only two pairs are illustrated here.) The R and r alleles segregate at anaphase I, yielding two types of/


Introduction to Genetics: Mendel and Meiosis

traits were on different chromosomes. are located on different chromosomes **Summary of Mendel’s Principles** 1. The inheritance of biological characteristics is determined by individual units known as genes. Genes are passed from parents to their offspring. 2. In cases in which two or more forms (alleles) of the gene for a single trait exist, some forms of the gene may be dominant and others may be recessive/


How does chromosome behavior account Chapter 15 - Chromosomal Basis of Inheritance AIM: How does chromosome behavior relate to Mendel? for Mendel’s Principles.

behavior relate to Mendel? for Mendel’s Principles ? (The chromosomal theory of inheritance) The chromosomal theory of inheritance: The Chromosome Theory of Inheritance: genes (allele pairs) are on chromosomes and homologous chromosomes segregate during meiosis (principle of segregation) and reunite during fertilization. If allele pairs are on different chromosomes they will sort independently (principle of independent assortment) due to independent orientation of the tetrads at metaphase I. If the/


Inheritance, Genes, and Chromosomes

Inheritance, Genes, and Chromosomes 8 Inheritance, Genes, and Chromosomes Chapter 8 Inheritance, Genes, and Chromosomes Key Concepts 8.1 Genes Are Particulate and Are Inherited According to Mendel’s Laws 8.2 Alleles and Genes Interact to Produce Phenotypes 8.3 Genes Are Carried on Chromosomes 8.4 Prokaryotes Can Exchange Genetic Material Chapter 8 Opening Question How is hemophilia inherited through the mother, and why is it more frequent in males? Early experiments with genetics yielded two/


Human Genetics and Biotechnology

are autosomes. The X and Y chromosomes are the sex chromosomes. Females have two X chromosomes, and males have one X and one Y. Human chromosomes contain a total of 20,000 to 22,000 genes, the majority of which have two or more alleles. • Linked genes are located on the same chromosome. Sex-linked genes are located on a sex chromosome, and X-linked genes are located on the X chromosome. The frequency of crossing/


Remington Grenier, Mercedes Cote, Tyana Nowlan, and Rebecca Isaacs.

Assortment - Mendel’s second law, stating the each pair of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes. Chromosome theory of inheritance- states that mendillian genes have specific loci along chromosomes and it’s the chromosomes that undergo segregation and independent assortment Wild type- the phenotype for the characteristic most commonly/


Inheritance, Genes, and Chromosomes

Inheritance, Genes, and Chromosomes 8 Inheritance, Genes, and Chromosomes Chapter 8 Inheritance, Genes, and Chromosomes Key Concepts 8.1 Genes Are Particulate and Are Inherited According to Mendel’s Laws 8.2 Alleles and Genes Interact to Produce Phenotypes 8.3 Genes Are Carried on Chromosomes 8.4 Prokaryotes Can Exchange Genetic Material Chapter 8 Opening Question How is hemophilia inherited through the mother, and why is it more frequent in males? Early experiments with genetics yielded two/


Chapter 14 The Human Genome

. a change in a DNA base b. an extra chromosome c. genes d. alleles In humans, a male has a. one X chromosome only. b. two X chromosomes. c. one X chromosome and one Y chromosome. d. two Y chromosomes. In humans, a male has a. one X chromosome only. b. two X chromosomes. c. one X chromosome and one Y chromosome. d. two Y chromosomes. Human females produce egg cells that have a. one/


Chapter 11- Genetics Meiosis Principles of genetics require:

units of inheritance Each trait controlled by one gene with two contrasting forms Alleles- alternate forms of a gene Chapter 11- Genetics Second conclusion called the principle of dominance: Some alleles are dominant and others are recessive Dominant- an allele of a gene that is always expressed (T) Recessive- an allele of a gene that is expressed only when the dominant allele is not present (t) Chapter 11- Genetics Segregation/


Allele Important Genetic Concepts Genotype Phenotype Gene.

Gene Frequency of CF Mutant Alleles ~ 70% of CF Mutant alleles are ∆F508 ∆F508 Mutation Healthy Lung Lung epithelial cells Lung epithelial cells AA or Aa Lung epithelial cells Lung epithelial cells Cystic Fibrosis Lung aa Erythropoietin Receptor Mutation And/-fluorouracil CB1954Alkylating agent EnzymeProdrugToxic Metabolite Gene Therapy for Cancer M-Phase Chromosome Interphase (G1, S, G2) Chromosomes Giemsa Stain Human Euploid Karyotypes FemaleMale Fig. 7-6 Homologous Chromosomes PM P = Paternal M /


MENDEL AND THE GENE IDEA

parallels between the behavior of chromosomes and the behavior of Mendel’s factors. Around 1902, Walter Sutton, Theodor Boveri, and others noted these parallels and a chromosome theory of inheritance began to take form. CHROMOSOMAL THEORY OF INHERITANCE Chromosomes are carriers of traits and each chromosome could carry the genes for MANY traits. Alternate forms or ALLELES of a gene are located on matched pairs of chromosomes. When chromosome pairs separate in meiosis, each/


Mendelian Genetics and the Inheritance of Genetic Traits

Pedigree of Alkaptonuria Table 9.9 SEX CHROMOSOMES AND SEX-LINKED GENES A human male has one X chromosome and one Y chromosome A human female has two X chromosomes Whether a sperm cell has an X or Y chromosome determines the sex of the offspring Human sex-linkage SRY gene: gene on Y chromosome that triggers the development of testes Fathers= pass X-linked alleles to all daughters only (but not/


The Chromosomal Basis of Inheritance Updated November 2008

techniques, cytologists worked out the process of mitosis in 1875 and meiosis in the 1890s. Chromosomes and genes are both present in pairs in diploid cells. Homologous chromosomes separate and alleles segregate during meiosis. Fertilization restores the paired condition for both chromosomes and genes. The chromosome theory of inheritance states that Mendelian genes have specific loci on chromosomes During meiosis chromosomes undergo: Segregation Independent assortment Around 1902, Walter Sutton, Theodor/


Cell Reproduction: Mitosis & Meiosis Chapter 8 (and the beginning of Chapter 10)

gene Homologous chromosomes Pair of chromosomes that carry genes for same heritable traits Except sex chromosomes (X or Y) Genes Sequences of chromosomal DNA Contain heritable information to make new individuals Individuals have pairs of genes on pairs of chromosomes Each member of pair of gene = allele Allele One of the variant forms of a gene at a particular (locus) location on a chromosome Different alleles/body (also very small) Other gets most of cytoplasm and develops into ovum (egg) 1 st polar body’s /


(a) describe, with the aid of diagrams and photographs, the behaviour of chromosomes during meiosis, and the associated behaviour of the nuclear envelope,

the same bivalent, resulting in similar sections of chromatid being swapped over. Often these sections will contain the same genes but different alleles. Crossing over produces new combinations of alleles on the chromatids The chiasmata remain in place during metaphase, holding the maternal and paternal chromosomes together on the equator, so that when they segregate at anaphase I, one member of each pair goes to/


Genetics Chromosome Number Fruit fly example: 8 chromosomes total

functional units of inheritance Each trait controlled by ___ gene with ___ contrasting forms _______- alternate forms of a gene Genetics Second conclusion called the principle of __________: Some alleles are _______ and others are ________ ________- an allele of a gene that is always expressed (__) _________- an allele of a gene that is expressed only when the dominant allele is not present (__) Genetics Segregation What had/


Unit 6 - Genetics Introduction

.gif Remember if the organism has identical alleles (SS or ss) it is said to be homozygous. An organism that has two different alleles for a trait it is considered heterozygous /genes/17gene.gif The shaded areas represent a gene that controls a specific trait(s). Gene maps are now widely used in understanding genetic mutations, sickness, and the human genome project. Fruit Flies Fruit flies (as shown here) are used to study genes and genetic relationships because they have a small number of chromosomes and/


University of California accessed 07.04.08 Chromosomes, Genes, Alleles Chromosomes, Genes, Alleles.

.ipm.ucdavis.edu/NEWS/aromatherapy-news.html accessed 07.04.08 Chromosomes, Genes, Alleles Chromosomes, Genes, Alleles Meiosis Theoretical Genetics Theoretical Genetics Genetic Engineering Genetic Engineering Europa http://ec.europa.eu/research/quality-of-life/arabidopsis.html accessed 07.04.08 A. Chromosomes A. Chromosomes B. Genes and Alleles B. Genes and Alleles C. Mutations C. Mutations A. Chromosomes 1. Eukaryote chromosomes are made of DNA and protein 2. DNA usually exists in the nucleus as chromatin/


Ch 7 Extending Mendelian Genetics. Studying Human Genetics A pedigree is a chart for tracing genes in a family. – Used to determine the chances of offspring.

organism Autosomes-pairs 1-22 Sex chromosomes-X and Y Genes vs. Alleles We have two of each chromosome – One from each parent Both chromosomes have the same gene, but may be different alleles for those genes Different alleles can produce different phenotypes – Ex: white or purple flowers Phenotype can depend on interactions of alleles. Incomplete dominance=neither allele is completely dominant nor completely recessive. Codominant alleles =both alleles will be completely expressed. –Codominant/


12 Inheritance, Genes, and Chromosomes. 12 Inheritance, Genes, and Chromosomes 12.1 What Are the Mendelian Laws of Inheritance? 12.2 How Do Alleles Interact?

segments. The exchange involves two chromatids in the tetrad; both chromatids become recombinant. Working with Data 12.2: Some Alleles Do Not Sort Independently Thomas Hunt Morgan studied linked genes by doing F 1 × homozygous recessive test crosses. They hypothesized that genes are linked together on chromosomes and that crossing over during meiosis gives rise to less frequent phenotypes. Working with Data 12.2: Some/


Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece.

two true-breeding pea plants, we follow two genes through the F 1 and F 2 generations. The two genes specify seed color (allele Y for yellow and allele y for green) and seed shape (allele R for round and allele r for wrinkled). These two genes are on different chromosomes. (Peas have seven chromosome pairs, but only two pairs are illustrated here.) The R and r alleles segregate at anaphase I, yielding two types/


Chapter # - Chapter Title $100 $200 $300 $400 $500 $100$100$100 $200 $300 $400 $500 Human Heredity Human Chromosomes Human Molecular Genetics Human Heredity.

. Both the X and Y chromosome. BACK TO GAME ANSWER Human Chromosomes: $200 Answer Question: Most sex-linked genes are located on a. The autosomes. b. The X chromosome only. c. The Y chromosome only. d. Both the X and Y chromosome. BACK TO GAME Human Chromosomes: $300 Question Question: Which of the following statements is true? a. Females cannot have hemophilia. b. A sex-linked allele cannot be dominant/


12345 How many chromosomes are shown in a normal human karyotype? 1.2 2.23 3.44 4.46.

a DNA base 2.an extra chromosome 3.genes 4.alleles 12345 In humans, a male has 1.one X chromosome only. 2.two X chromosomes. 3.one X chromosome and one Y chromosome. 4.two Y chromosomes. 12345 Human females produce egg cells that have 1.one X chromosome. 2.two X chromosomes. 3.one X or one Y chromosome. 4.one X and one Y chromosome. 12345 What is the approximate probability/


Heredity and Genetics. Heredity 1. Is it possible for two parents with blue eyes to have a brown eyed child? 2. Is it possible for two parents with brown.

characteristic of an organism ◦ Example: flower color Gene – part of a chromosome that helps determine a specific trait ◦ Example: flower color gene Allele – a form of a gene ◦ Example:  One allele is the “blue” form of the gene  One allele is the “red” form of the gene Chromosomes come in pairs Cut out from picture and match each in pairs How many chromosomes? Humans = 23 chromosome pairs, or 46 total. We think we/


Genetics Heredity Lesson 1 Do Now Video: What are genes?What are genes.

others –brown eye color masked blue How does this work? eye color (brown?) hair color eye color (blue?) Paired chromosomes have same kind of genes –but may be different alleles In Class Assignment Hereditary Simulation Worksheet Determining your genes worksheet Homework History and Terminology worksheet Punnett Crosses Lesson 2 Do Now Take out Homework from last night & begin looking over the questions for the video/


Monday3/19/12 AIM: What is heredity? Homework: Handout Section 11.2 Read pages 288-291. Reading check on page 288. 2- Use figure 11.7 and in your own words,

pairs of Autosomes –1 sex pair –Totaling 23 pairs = 46 Genes are carried on chromosomes and contain the directions to build a protein One gene codes for one protein The chromosomal basis of inheritance Genes are located on chromosomes Inheritance pertains to the behavior of chromosomes during meiosis and fertilization Gene locus: the actual position of an allele on a chromosome Some gene loci are very close together Tuesday 4/17/12 AIM/


Humans: Reproduce sexually with internal fertilization The purpose of sex, of course, is to get an egg fertilized by a sperm, combining the chromosomes.

, electrical signals, contraction, metabolism, cell death, etc.) Two genes for the same trait, carried on different chromosomes of a pair (one from your father, one from your mother), are called alleles These alleles may be the same (e.g. both alleles for making earwax), or These alleles may be different (e.g. one allele for blue eyes and one allele for brown eyes You are considered homozygous for a/


Location of Genes The position of a gene on a chromosome is the locus. In sexually reproducing organisms, most cells have a homologous pair of chromosomes.

for that gene. Alleles These two different versions of gene A create a condition known as heterozygous. Only the dominant allele (A) will be expressed. When both chromosomes have identical copies of the recessive allele for a gene, the organism is said to be homozygous recessive for that gene. Genes occupying the same locus or position on a chromosome code for the same trait and are said to be alleles. Paternal chromosome that/


Genetics: The Science of Heredity 1.- Introduction 2.- Mendelian genetics 3.- Chromosomal theory of inheritance 4.- Mutations 5.- Human Inheritance.

of bases between two copies of a gene would mean that these two copies are different alleles. Notice that each chromosome in the pair has the same genes. This genes are lined up in the same order on both chromosomes. However, the alleles for some of the genes might be different. For example, the organism has the A allele on one chromosome and the a allele on the other. As you can/


HUMAN REPRODUCTION BIOLOGY 269. Humans: Reproduce sexually with internal fertilization All cells in adult except gametes contain 46 chromosomes; sperm.

blond hair) You are considered homozygous for a trait if both alleles are the same, or heterozygous if the two alleles are different While all cells (except sperm and eggs) CONTAIN all of the chromosomes and thus all of the genes Not all of the cells EXPRESS all of their genes That is: only some of the genes will be expressed in any particular cell. e.g. skin/


Forensics and Probability. Origin of Variation? Charles Darwin from, On the Origin of Species by Means of Natural Selection, 1859 "...no-one can say.

know about genes and chromosomes Alternative versions of genes account for variations in inherited characters For example, the gene for flower color in pea plants exists in two versions, one for purple flowers and the other for white flowers These alternative versions of a gene are now called alleles Each gene resides at a specific locus on a specific chromosome The First Concept Allele for purple color Homologous pair of chromosomes Allele for/


 Identify some patterns of inheritance in humans.  Describe the function of the sex chromosomes.  Explain the relationship between genes and the environment.

have an X chromosome and half will have a Y chromosome.  If a sperm with an X chromosome fertilizes an egg, the baby will be a girl.  If a sperm with a Y chromosome fertilizes an egg, the baby will be a boy.  The genes for some traits are carried on the sex chromosomes.  Genes on the X and Y chromosomes are often called sex-linked genes because their alleles are passed/


Theoretical Genetics 4.3. 4.3.1 Define genotype, phenotype, dominant allele, recessive allele, recessive allele, codominant alleles, locus, homozygous,

the X chromosome and absent from the shorter Y chromosome in in humans GENES CARRIED ON THE SEX CHROMOSOME Because the Y chromosome is significantly smaller than the X chromosome, it has fewer loci and therefore fewer genes than the X chromosome. This means that in males, the majority of alleles present on the X chromosome have no alleles to pair with on the smaller Y chromosome. The X chromosome is relatively larger and several genes located/


CHAPTER 15 THE CHROMOSOMAL BASIS OF INHERITANCE Section A: Relating Mendelism to Chromosomes 1.Mendelian inheritance has its physical basis in the behavior.

a physical basis in the behavior of chromosomes. Mendel’s hereditary factors are the genes located on chromosomes. Introduction Around 1900, cytologists and geneticists began to see parallels between the behavior of chromosomes and the behavior of Mendel’s factors. Chromosomes and genes are both present in pairs in diploid cells. Homologous chromosomes separate and alleles segregate during meiosis. Fertilization restores the paired condition for both chromosomes and genes. 1. Mendelian inheritance has its/


Chapter 12 Chromosomes & Human Inheritance OCC BIO-114.

result of recombination, new allele combinations are formed, and we have more genetic variation. crossing over segments of homologous chromosomes are exchanged w/ each other at site called chiasmata during meiosis I segments of homologous chromosomes are exchanged w/ each other at site called chiasmata during meiosis I forms new gene combinations on both homologous chromosomes forms new gene combinations on both homologous chromosomes gene combinations for daughter cell/


Mr. Karns Biology, Seventh Edition Chapter 15 The Chromosomal Basis of Inheritance.

two weeks – They have only four pairs of chromosomesAnd.. They are very large! (the chromosomes) Morgan first observed and noted – Wild type, or normal, phenotypes that were common in the fly populations Traits alternative to the wild type – Are called mutant phenotypes Figure 15.3 Correlating Behavior of a Gene’s Alleles with Behavior of a Chromosome Pair In one experiment Morgan mated male flies with/


Human Gene Mapping & Disease Gene Identification.

the X, there is no recombination involving the X-linked portion of the X chromosome in a male, and he will pass the hemophilia mutation h and allele M together. The phase in his daughter must be that h and M are in coupling  Two major approaches to locate and identify genes that predispose to complex disease or contribute to genetic variance of quantitative traits 1. Affected/


CHAPTER 11 MENDEL & MUTATIONS Father of Genetics  Monk and teacher.  Experimented with purebred tall and short peas.  Discovered some of the basic.

stature sterile female with webbed neck and diminished stature Figure 11.26 Nondisjunction of the X chromosome 11.9 The Role of Mutations in Human Heredity Accidental changes in genes are called mutations Accidental changes in genes are called mutations mutations occur only rarely and almost always result in recessive alleles mutations occur only rarely and almost always result in recessive alleles not eliminated from the population because/


Cancer and Genetics: What’s the Connection? Supported by a grant from Supported by a grant from the National Cancer Institute 1R25CA93426 1R25CA93426 Administered.

gene allele on one number 9 chromosome, and an “A” blood type gene allele on the other number 9 chromosome, the person is homozygous for that trait and will express the A blood type. Allele: If a person has two different alleles for a single gene trait, the person is heterozygous for that trait. So, if a person has an “A” blood type gene allele on one number 9 chromosome, and a “B” blood type gene allele/


Genetic Inheritance MENDEL & MUTATIONS Father of Genetics  Monk and teacher.  Experimented with purebred tall and short peas.  Discovered some of.

sterile female with webbed neck and diminished stature Nondisjunction of the X chromosome The Role of Mutations in Human Heredity The Role of Mutations in Human Heredity Accidental changes in genes are called mutations Accidental changes in genes are called mutations mutations occur only rarely and almost always result in recessive alleles mutations occur only rarely and almost always result in recessive alleles not eliminated from the population/


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