2 A genetic disorder that is caused by abnormality in an individual's DNA. Abnormalities can range from small mutation in a single gene to the addition or subtraction of a whole chromosome or set of chromosomes. Incidence: - Nearly 3-5 % of all diseases in general populations have genetic causes.
3 Classification Inherited diseases can be classified into 4 main groups: I. Chromosomal disorders II. Monogenic disorders III. Multigenic ( multifactorial) disorders IV. Mitochondrial disorders
4 1. Chromosomal disorders Abnormalities in chromosomal numbers or structure (cytogenetics). Also it is called chromosome aberrations, which are two types: Numerical and Structural. Numerical changes are either polyploidy when the changes involves a set number of chromosomes or aneuploidy in which the changes is limited to the number of individual chromosomes. The incidence of aneuploidy is usually more common than polyploidy.
5 Polyploidy occurs in humans as triploidy, with 69 chromosomes (sometimes called 69,XXX), or tetraploidy with 92 chromosomes (sometimes called 92,XXXX). Triploidy, is usually responsible for 17 % of spontaneous abortions. The main causes include fertilization with diploid spermatocyte or the fertilization with a single normal egg by two sperms.
7 In aneuploidy, an extra or missing chromosome is a common cause of genetic disorders (birth defects). Some cancer cells also have abnormal numbers of chromosomes. Aneuploidy occurs during cell division in the form of monosomies or trisomies (disomies is normal), when the chromosomes do not separate properly between the two cells. This generally happens when the cytokinesis occurring properly while the karyokinesis occurring incompletely.
9 Usually aneuploidy causes the termination of developing fetus, but there can be cases of live birth incidences. The most frequently extra chromosomes among live births occurring in numbers 13, 18 and 21. An example of a chromosomal aneuploidy is Down syndrome, or trisomy 21, which is associated with mental retardation and other birth defects, such as heart problems.
11 Another example is Turner syndrome, which is caused by the absence of one sex chromosome (monosomy).
12 Although most Turner patients are infertile, there have been few cases of fertility but these women have increased risk of chromosomal errors and high incidence of fetal miscarriage (premature termination of fetus). 1. Chromosome structural changes involve the loss or gain of portions in chromosomes, due to : deletion, inversion, duplication and translocation
13 2. Monogenic disorders A genetic mutation that involves single allele on nuclear chromosome and follows classical Mendelian inheritance. The primary genetic defect is usually a point or frame shift mutations. Such genetic changes may affect the synthesis of structural or transport protein, receptor, coagulation factor, immunoglobulin, peptide hormone, natural inhibitor, or an enzyme. Also called In born errors of metabolism which means inherited defect involving one of the steps in certain metabolic pathway.
14 The severity of mutation depends on the function of protein being affected : Some mutations can be harmless like pentosuria & fructosuria (Appearance of pentose and fructose sugars in urine due to defect in their metabolisms). Others can be harmful due to decreased formation of an important structural protein like collagen or receptor protein like LDL receptor or regulatory natural inhibitor like α1-antitrypsin or some enzymatic defect in metabolism that causes one of the following metabolic changes:
15 1. Decrease in the rate of product formation Deficiency of glucose 6-phosphatase. A liver enzyme in glycogen catabolic pathway leads to reduced formation of glucose from glucose-6-phosphate. The genetic disease is called Von Gierke s glycogen storage disease in which liver abnormally accumulates glycogen without being able to degrade glycogen into glucose.
16 2. Decrease in the rate of substrate removal The deficiency of phenyl alanine hydroxylase enzyme leads to accumulation of phenyl alanine substrate as well as its chemically deaminated products phenylketones, which appears in urine due to their excessive formation (Phenylketonuria disease or PKU). Normally this enzyme converts the amino acid phenylalanine to the amino acid tyrosine, therefore patients with PKU have low levels of tyrosine. The high levels of phenylalanine metabolites affect neuronal development, which leads to mental retardation.
17 The symptoms associated with this disease can be prevented by proper nutrition. Phenylalanine is an amino acid found in many proteins; therefore, patients affected with PKU can escape the disease by strictly limiting themselves to low protein diets. Providing that PKU be detected early, a proper nutrition lacking phenylalanine will prevent the disease development.
18 3. Altered feedback control Cortisol hormone is synthesized in the adrenal gland from cholesterol in a pathway requires the enzyme 21-hydroxylase.Excessive formation of cortisol can inhibit this pathway by feedback inhibition. Deficiency of 21-hydroxylase enzyme causes reduced formation of cortisol which stops the feedback control mechanism and leads to increase secretion of adrenocorticotrophic hormone (ACTH) in a disease called Congenital adrenal hyperplasia. 21-Hydroxylase Cholesterol Cortisol
19 CRH=Corticotropin releasing hormone
20 Pedigree It is a family of genetic tree which describes the interrelationship between parents & children for a particular trait. The pedigree not only gives genetic information about the history of the family for certain trait, but also can predict to some extent the segregation of this trait in future generations.
21 In a pedigree, the following symbols are used: Squares( ) Males Circles ( ) Females. Horizontal lines connect male and female mating. Vertical lines extending downward from a couple their children. Dark color individuals affected by the disease White color healthy individuals.
22 Mode of inheritance for monogenic disorders: The mode of inheritance for monogenic disorders can be either autosomal dominant or autosomal recessive or sex linked. 1-Autosomal dominant disorder Autosomal ( defective gene is present on one of the 22 somatic( non-sex ) chromosome pairs).the phenotypic properties of the dominant disorder (symptoms) will appear even when the individual has mutation in only one copy of the two gene alleles ( heterozygous).in fact the homozygous state of this dominant mutation is usually lethal causing spontaneous abortion in pregnant women.
23 Males and females are affected with equal frequency, which can occur in each generation. The child of an affected individual has a 50 % risk of inheriting the mutated gene. The trait does not skip a generation. Where one parent is affected, about half of the progeny will be affected.
24 Selected examples Familial hyperlipidemia: Abnormal increase of all lipid fractions in plasma. Familial hypercholesterolemia: Abnormal increase of cholesterol in plasma Spherocytosis: Hemolytic type of anemia due to the formation of abnormal spherical RBC shape instead of the normal disc shape.
25 Pedigree of autosomal dominant trait Example. Wooly hair results from a dominant allele; therefore, individuals who are homozygous dominant (WW) or heterozygous (Ww) have this trait. Individuals who are homozygous recessive (ww) for this gene have normal hair. The man at the top of the pedigree has normal hair, so his genotype is ww. His wife has wooly hair, but must be heterozygous (Ww) since three of their six children have normal hair.
26 Wooly hair
27 2-Autosomal recessive disorders These disorders range in severity from traits that are mild such as Albinism to those very severe like Cystic fibrosis.the heterozygous individual of this mutation is a normal carrier or some times shows mild clinical symptoms (e.g.thalasemia).thus recessively autosomal disorder shows up a disease symptoms only in the homozygous individuals who inherit one recessive allele from each parent.
28 The majority of individuals affected with recessive disorders are born to normal parents who are both carriers. These individuals carry 25 % risk of disease incidence compared with 25 % chance of normal genotype and 50 % probability of a heterozygous carriers. If one of the parent is a carrier and the other is homozygous for the recessive defect then the probability of disease is increased to 50 % for each child.
29 The clinical expression of autosomal recessive disorders is usually more predictable than in autosomal dominant disorders. That is most recessively mutated alleles lead to a complete or partial loss of protein functions. In addition, lethal alleles are more common in recessive than in autosomal dominant inheritance because the effects of lethal allele are masked in the heterozygous state.
30 Selected examples Phenylketonuria Thalasemia = Defective hemoglobin due to the formation of short α or β chains resulted from frame shift mutation. Sickle cell disease= Abnormal precipitation of hemoglobin due to substitution mutation in β- chains of hemoglobin that change the shape of hemoglobin to curved shape instead of disk shape.
31 Pedigree for autosomal recessive disorder
32 This figure shows the pattern of albinism inheritance that can be observed for a recessive trait. The half-filled symbols indicate carriers (heterozygotes). An individual expressing a recessive trait (homozygous recessive) may not appear in every generation.
33 3. Sex linked disorders Genes carried either on the y or x sex chromosomes are said to be sex linked. Disorders, which are transmitted as y- linked, are very rare. In contrast, the x-linked defective alleles can be inherited as x- linked either recessive or dominant disorders similar to that of the autosomal genetic transmittance.
34 As females have two x-chromosomes they will be unaffected carriers of x- linked recessive disease, unless they are homozygous for the mutated allele(very rare).however males who have only one copy of the x chromosome will develop the clinical symptoms of the disease from the mutated allele.
35 Selected examples Hemophilia: defect in one of the clotting factors in blood Duchenne muscular dystrophy: defect in membrane protein called dystrophine, which is present in muscle cells. The defect leads to muscle weakening.
36 X-Linked Recessive Pedigree Completely affected mother can pass the disease to their sons, but the daughters will remain carriers.
37 X-Linked dominant The x-linked dominant disorder is rare, which shows the clinical symptoms in the heterozygous female or in a male with single copy of the mutated allele. Both Males and Females carrying a single copy of the allele are affected. Females will pass the disease to half of their children in a sexunspecific manner. Males will pass the disease to all their daughters but none to their sons.
39 An X-linked dominant form of the disease hypophosphatemia (a form of rickets) exists. This disease occurs due to an excess excretion of phosphates from the body, which results in bones being unable to properly calcified and having short stature.
40 Y-Linked dominant Males always affected by the disease because they carry a copy of the mutated allele. All sons inherited the disease from their fathers while daughters are free of the disease.
42 Y-linked diseases are generally rare because there are very few genes present on this relatively small chromosome. Only those genes important to spermatogenesis are mainly found on this chromosome, and therefore their defect is linked to male infertility. One such condition, Sertoli syndrome, results in the complete absence of the germ cells in the male testis.
Lecture 17: Human Genetics I. Types of Genetic Disorders A. Single gene disorders B. Multifactorial traits 1. Mutant alleles at several loci acting in concert C. Chromosomal abnormalities 1. Physical changes
Lab Activity 36 Principles of Heredity Portland Community College BI 233 Terminology of Chromosomes Homologous chromosomes: A pair, of which you get one from mom, and one from dad. Example: the pair of
What You ll Learn You will compare the inheritance of recessive and dominant traits in humans. You will analyze the inheritance patterns of traits with incomplete dominance and codominance. You will determine
mutation) Pedigrees mutation) 1. Autosomal recessive inheritance: this is the inheritance of a disease through a recessive allele. In order for the person to have the condition they would have to be homozygous
Gene Expression and Mutation GENE EXPRESSION: There are hormonal and environmental factors that may cause the expression of some genetic information. Some examples are: 1. The two- colour pattern of some
24 - Aya Alomoush - Talal Al-Zabin - Belal Azab 1 P a g e 1) Features of autosomal dominant inheritance: A) Vertical transmission: direct transmission from grandparent to parent to child without skipping
Chapter 4 PEDIGREE ANALYSIS IN HUMAN GENETICS Chapter Summary In order to study the transmission of human genetic traits to the next generation, a different method of operation had to be adopted. Instead
Genetic Disorders PART ONE: Detecting Genetic Disorders Amniocentesis Chorionic villus sampling Karyotype Triple Screen Blood Test Amniocentesis A technique for determining genetic abnormalities in a fetus
Human Genetic Disorders HOMOLOGOUS CHROMOSOMES Human somatic cells have 23 pairs of homologous chromosomes 23 are inherited from the mother and 23 from the father HOMOLOGOUS CHROMOSOMES Autosomes o Are
Units of Heredity: Chromosomes and Inheritance Ch. 12 12.1 in Humans X-chromosomes also have non genderspecific genes Called X-linked genes Vision Blood-clotting X-linked conditions Conditions caused by
MCAT Biology Problem Drill PS07: Mendelian Genetics Question No. 1 of 10 Question 1. The smallest unit of heredity is. Question #01 (A) Cell (B) Gene (C) Chromosome (D) Allele Cells contain the units of
Genetics, Mendel and Units of Heredity ¾ Austrian monk and naturalist. ¾ Conducted research in Brno, Czech Republic from 1856-1863 ¾ Curious about how traits were passed from parents to offspring. Gregor
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 having a certain genetic disorder. Karyotype=picture
Classifications of genetic disorders Dr. Liqaa M. Sharifi Human diseases in general can roughly be classified in to: 1-Those that are genetically determined. 2-Those that are almost entirely environmentally
NOTES: 14.1-14.2: HUMAN HEREDITY Human Genes: The human genome is the complete set of genetic information -it determines characteristics such as eye color and how proteins function within cells Recessive
Genetic Diseases SCPA202: Basic Pathology Amornrat N. Jensen, Ph.D. Department of Pathobiology School of Science, Mahidol University email@example.com Genetic disease An illness caused by abnormalities
Human Heredity: The genetic transmission of characteristics from parent to offspring. Karyotype : picture of the actual chromosomes arranged in pairs, paired and arranged from largest to smallest. Human
Basic Definitions Chromosomes There are two types of chromosomes: autosomes (1-22) and sex chromosomes (X & Y). Humans are composed of two groups of cells: Gametes. Ova and sperm cells, which are haploid,
Chapter 28 Modern Mendelian Genetics (I) Gene-Chromosome Theory Genes exist in a linear fashion on chromosomes Two genes associated with a specific characteristic are known as alleles and are located on
Pedigree Analysis Introduction A pedigree is a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships. These diagrams make it easier to visualize
Agro/Ansc/Bio/Gene/Hort 305 Fall, 2017 MEDICAL GENETICS AND CANCER Chpt 24, Genetics by Brooker (lecture outline) #17 INTRODUCTION - Our genes underlie every aspect of human health, both in function and
Human Heredity Chapter 5 Human Genetics 5:1 Studying Human Genetics Humans are not good subjects for genetic research because: 1. Humans cannot ethically be crossed in desired combinations. 2. Time between
Lesson Overview Karyotypes A genome is the full set of genetic information that an organism carries in its DNA. A study of any genome starts with chromosomes, the bundles of DNA and protein found in the
Name Date Pedigree Construction Notes GO TO à Mendelian Inheritance (http://www.uic.edu/classes/bms/bms655/lesson3.html) When human geneticists first began to publish family studies, they used a variety
Genetics Supplement (These supplementary modules, a Genetics Student Handout, and Teacher Preparation Notes with suggestions for implementation are available at http://serendip.brynmawr.edu/sci_edu/waldron/#genetics.
Name Date Period Chapter 7: Pedigree Analysis B I O L O G Y Introduction: A pedigree is a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships.
Genetics Supplement (These supplementary modules, a Genetics Student Handout, and Teacher Preparation Notes with background information are available at http://serendip.brynmawr.edu/sci_edu/waldron/#genetics.
Chapter 7 Learning Outcomes Explain the concept of a single-gene trait Describe Mendel s contributions to the field of genetics Be able to define the terms gene, allele, dominant, recessive, homozygous,
Single Gene (Monogenic) Disorders Mendelian Inheritance: Definitions A genetic locus is a specific position or location on a chromosome. Frequently, locus is used to refer to a specific gene. Alleles are
Human Genetic Mutations 2 Main Types of Mutations 1.) Chromosomal Mutations 2.) Gene Mutations What are chromosomes? Humans have 23 pairs of chromosomes, with one chromosome from each parent. The chromosomes
Name: Date: Block: 1 Review Packet for Genetics and Meiosis Directions: Answer the questions and where indicated, draw a Punnett square and show all work! 1. Who was Gregor Mendel? Where did he live and
Meiotic Mistakes and Abnormalities Learning Outcomes 5.6 Explain how nondisjunction can result in whole chromosomal abnormalities. (Module 5.10) 5.7 Describe the inheritance patterns for strict dominant
Genetics Review 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
Unit 7 Genetics Review Outline Pre-AP Biology 2017-2018 LT 1 - I can explain the relationships among alleles, genes, chromosomes, genotypes, and phenotypes. This target covers application of the vocabulary
Pedigree Analysis Why do Pedigrees? Punnett squares and chi-square tests work well for organisms that have large numbers of offspring and controlled mating, but humans are quite different: Small families.
Genetics 1 by Drs. Scott Poethig, Ingrid Waldron, and. Jennifer Doherty, Department of Biology, University of Pennsylvania, Copyright, 2011 We all know that children tend to resemble their parents in appearance.
Chapter 11 Chromosomes and Human Inheritance Human Chromosomes Human body cells have 23 pairs of homologous chromosomes 22 pairs of autosomes 1 pair of sex chromosomes Autosomesand Sex Chromosomes Paired
Unit 3 Chapter 16 Genetics & Heredity Biology 3201 Intro to Genetics For centuries, people have known that certain physical characteristics are passed from one generation to the next. Using this knowledge,
Genetic Diseases SCPA202: Basic Pathology Amornrat N. Jensen, Ph.D. Department of Pathobiology School of Science, Mahidol University firstname.lastname@example.org Genetic disease An illness caused by abnormalities
Chapter 15 Notes The Chromosomal Basis of Inheritance Mendel s hereditary factors were genes, though this wasn t known at the time Now we know that genes are located on The location of a particular gene
Chromosomes and Human Inheritance Chapter 11 11.1 Human Chromosomes Human body cells have 23 pairs of homologous chromosomes 22 pairs of autosomes 1 pair of sex chromosomes Autosomes and Sex Chromosomes
Patterns in Inheritance Chapter 10 What you absolutely need to know Punnett Square with monohybrid and dihybrid cross Heterozygous, homozygous, alleles, locus, gene Test cross, P, F1, F2 Mendel and his
Chapter 11 Gene Expression 11-1 Control of Gene Expression Gene Expression- the activation of a gene to form a protein -a gene is on or expressed when it is transcribed. -cells do not always need to produce
Meiosis and Genetics Humans have chromosomes in each cell What pattern do you notice in the human karyotype (a technique that organizes chromosomes by type and size)? Humans are diploid 1 Gametes are produced
Genetics DNA contains the genetic code for the production of. A gene is a part of DNA, which has enough bases to make for many different proteins. These specific proteins made by a gene decide the of an
Genetics DNA contains the genetic code for the production of. A gene is a segment of DNA, which consists of enough bases to code for many different proteins. The specific proteins produced by a gene determine
29 CHAPTER 5 PRINCIPLE OF INHERITANCE AND VARIATION MULTIPLE-CHOICE QUESTIONS 1. All genes located on the same chromosome: a. Form different groups depending upon their relative distance b. Form one linkage
Unifactorial or Single Gene Disorders Hanan Hamamy Department of Genetic Medicine and Development Geneva University Hospital Training Course in Sexual and Reproductive Health Research Geneva 2011 Single
Mendelian Genetics and Beyond Chapter 4 Study Prompts 1. What is a mode of inheritance? 2. Can you define the following? a. Autosomal dominant b. Autosomal recessive 3. Who was Gregor Mendel? 4. What did
Class XII - Biology Principle of Inheritance and Variation Chapter-wise Questions MULTIPLE-CHOICE QUESTIONS 1. All genes located on the same chromosome: a. Form different groups depending upon their relative
Name: Class key Period: Chapter 11 assignments Pages/Sections Date Assigned Date Due Topic: Recessive Genetic Disorders Objective: Describe some recessive human genetic disorders. _recessive_ alleles are
Inheritance The passing of traits from parents to offspring Genetics The scientific study of the inheritance Gregor Mendel -Father of modern genetics -Used peas to successfully identify the laws of heredity
SEX-LINKED INHERITANCE Dr Rasime Kalkan Human Karyotype Picture of Human Chromosomes 22 Autosomes and 2 Sex Chromosomes Autosomal vs. Sex-Linked Traits can be either: Autosomal: traits (genes) are located
Welcome Back! 2/6/18 1. A species of mice can have gray or black fur and long or short tails. A cross between blackfurred, long-tailed mice and gray-furred, shorttailed mice produce all black-furred, long-tailed
Genetics in Primary Care Curriculum Statement 6 Dr Dave Harniess PCME Stockport Learning Objectives Understanding of genetic component of disease Screening for genetic conditions and risk assessment in
Semester 2- Unit 2: Inheritance heredity -characteristics passed from parent to offspring genetics -the scientific study of heredity trait - a specific characteristic of an individual genes -factors passed
LECTURE 12 B: GENETIC AND INHERITANCE Mendel s Legacy Genetics is everywhere these days and it will continue as a dominant force in biology and society for decades to come. Wouldn t it be nice if people
Genetics - Problem Drill 06: Pedigree and Sex Determination No. 1 of 10 1. The following is a pedigree of a human trait. Determine which trait this is. (A) Y-linked Trait (B) X-linked Dominant Trait (C)
Genes are found on Chromosomes! genes and chromosomes are made up of DNA, which is the genetic material for all life on earth genes are found on a specific region on a chromosome; called a locus (loci)
Name Date Period Lab Activity Report: Mendelian Genetics - Genetic Disorders Background: Sometimes genetic disorders are caused by mutations to normal genes. When the mutation has been in the population
Human Genetics Notes: Human Chromosomes Cell biologists analyze chromosomes by looking at. Cells are during mitosis. Scientists then cut out the chromosomes from the and group them together in pairs. A
Genetics and Heredity Notes I. Introduction A. It was known for 1000s of years that traits were inherited but scientists were unsure about the laws that governed this inheritance. B. Gregor Mendel (1822-1884)
Review for Meiosis and Genetics Unit Test: Theory 1. What is a karyotype? What stage of mitosis is the best for preparing karyotypes? a karyotype is a picture of all of the chromosomes in a cell, organized
Name Period Chapter 15: The Chromosomal Basis of Inheritance Concept 15.1 Mendelian inheritance has its physical basis in the behavior of chromosomes 1. What is the chromosome theory of inheritance? 2.
Genetics: CH9 Patterns of Inheritance o o Lecture note Directions Highlight Key information (10-30% of most slides) My Thoughts: Questions, comments, additional information, connections to prior knowledge,
Honors Biology Review Sheet to Chapter 9 Test Name Per 1. Label the following flower: sepal, petal, anther, filament, style, ovary, stigma Draw in ovules and label. Color the female structure red and the
Human Genetics (Learning Objectives) Recognize Mendel s contribution to the field of genetics. Review what you know about a karyotype: autosomes and sex chromosomes. Understand and define the terms: characteristic,
Sex Determination Male = XY Female = XX 23 pairs of chromosomes (22 autosomes/body chromosomes, 1 sex) X chromosome----->large, rod shaped Y chromosome-----> smaller Mating of male & female XY x XX X Y
Mendel A. Mendel: Before Mendel, people believed in the hypothesis. This is analogous to how blue and yellow paints blend to make. Mendel introduced the hypothesis. This deals with discrete units called
Genetic Disorders A genetic disorder is an abnormality in the. They can range for a deletion of a gene to the deletion of an entire chromosome. List the types of genetic disorders. Williams Syndrome- A
Mendelian Genetics Vocabulary Genotype: o Capital letter = allele o Lowercase letter = allele o Ex AA, Aa, aa Phenotype: o Ex green, yellow Homozygous: o Homozygous dominant: o Homozygous recessive: Heterozygous:
Lecture 13: May 24, 2004 CH14: Mendel and the gene idea *particulate inheritance parents pass on discrete heritable units *gene- unit of inheritance which occupies a specific chromosomal location (locus)
Ch. 15 The Chromosomal Basis of Inheritance Nov 12 12:58 PM 1 Essential Question: Are chromosomes the basis of inheritance? Nov 12 1:00 PM 2 1902 Walter S. Sutton, Theodor Boveri, et al Chromosome Theory
Unit 2 Physiology and Health Part (a) The Reproductive System HOMEWORK BOOKLET Name: Homework Date Due Mark % Key Area 1 The structure and function of reproductive organs Key Area 2 Hormonal control of
GENETICS NOTES Chapters 12, 13, 14, 15 16 DNA contains the genetic code for the production of PROTEINS. A gene is a segment of DNA, which consists of enough bases to code for many different proteins. The
Name Class Date Review Guide Genetics The fundamental principles of genetics were first discovered by. What type of plant did he breed?. True-breeding parental plants are called the generation. Their hybrid
Name: Date: Class: (Exceptions to Mendelian Genetics Continued) Codominance Firstly, it is important to understand that the meaning of the prefix "co is "together" (i.e. cooperate = work together, coexist
Inheritance of Chromosomes How many chromosomes did our parents gametes contain when we were conceived? 23, 22 autosomes, 1 sex chromosome Autosomes are identical in both male & female offspring For the
Unit 3: DNA and Genetics Module 9: Human Genetics NC Essential Standard: 3.2.3 Explain how the environment can influence expression of genetic traits 3.3.3 Evaluate ethical issues surrounding the use of
Genetics and Heredity History Genetics is the study of genes. Inheritance is how traits, or characteristics, are passed on from generation to generation. Chromosomes are made up of genes, which are made
Human Genetic Diseases 1 2 2006-2007 3 4 5 6 Pedigree analysis Pedigree analysis reveals Mendelian patterns in human inheritance data mapped on a family tree = male = female = male w/ trait = female w/