350 likes | 481 Views
Human Genetics. Breaking Down the Definitions Honors. Sex chromosome Autosome Sex-linked trait Linked gene Chromosome map Map unit Germ-cell mutation Somatic-cell mutation Lethal mutation Deletion Inversion Translocation Nondisjunction Point mutation Substitution
E N D
Breaking Down the Definitions Honors • Sex chromosome • Autosome • Sex-linked trait • Linked gene • Chromosome map • Map unit • Germ-cell mutation • Somatic-cell mutation • Lethal mutation • Deletion • Inversion • Translocation • Nondisjunction • Point mutation • Substitution • Frameshift mutation • Insertion mutation • Pedigree • Carrier • Genetic disorder • Polygenic • Complex character • Multiple allele • Sex-influenced trait • Huntington’s Disease • Amniocentesis • Chorionic villi sampling • Genetic counseling • Gene therapy
Breaking Down the Definitions Reg. Bio • Karyotype • Sex chromosome • Autosome • Pedigree • Sex linked gene • Nondisjunction • DNA fingerprinting • Gene Therapy
Sex Chromosomes and Autosomes • The sex chromosomes contain genes that determine the gender of the individual. • Autosomes are the remaining chromosomes that do not affect the gender of the individual. • Males= XY • Females = XX
Gender Determination—What are the chances of having a girl or a boy??
Gene Location • Genes located on the X-Chromosome are called X-Linked Genes. • Genes located on the Y-Chromosome are called Y-Linked Genes. • The X Chromosome is much bigger than the Y Chromosome and therefore there are more genes on it. • A male with a recessive allele on the X chromosome will exhibit the recessive trait since there is not a counter-part on the smaller Y Chromosome.
Linked Genes • Pairs of genes that tend to be inherited together are called LINKED GENES. • The genes are linked together because they are found on the same chromosome • During crossing-over the genes can be swapped. • Video Clip—Crossing Over
Chromosome Mapping • The farther apart 2 genes are located on a chromosome, the more likely a cross over will occur. • Chromosome Map—a diagram that shows the linear placement of genes on a chromosome. • One MAP UNIT = 1% chance of crossing-over
Mutations • A MUTATION is a change in the nucleotide base sequence of DNA (the letters)
Chromosome Mutations • CHROMOSOME MUTATIONS are changes in the structure of a chromosome or the loss/gain of an entire chromosome
Mutation Video Clip • Give an example of an addition • Give an example of a deletion
Inheritance of Traits • A PEDIGREE is a diagram that shows how a trait is inherited over several generations • Squares = males, Circles = females • Filled symbol = has the trait, empty symbol= no trait • Horizontal line =mating, vertical line = offspring
Family Pedigree Practice! • Create a pedigree for eye color for the following family! • Children: • Suzy has brown eyes, Jose has brown eyes, Hiram has blue eyes, Damien has brown eyes. • Mom has blue eyes, Dad has blue eyes • On mom’s side: Grandma has brown eyes, grandpa has blue eyes • On dad’s side: grandma has blue eyes, grandpa has blue eyes
Weekly Homework!--Honors • Create a pedigree for your own family! • Choose 1 trait • attached ear lobes, color blindness, dimples, eye color, tongue rolling, second toe longer than big toe, gluten allergy, near sightedness, right/left handed, curly/straight hair • Go back at least to your grandparents, farther if you can. • Talk to people, look at pictures • If unknown, shade in gray • If trait is present-color red • If trait is absent, leave empty
Genetics Classroom Survey • After completing the survey answer the following: • Which 2-3 traits are the most common? • Which 2-3 traits are the least common? • Which gene of yours did you find to be common? • Which gene of yours did you find to be uncommon?
Genetic Disorders • GENETIC DISORDERS are diseases or disabling conditions that are passed down from parent to offspring • POLYGENIC are traits that are influenced by multiple genes rather than a single allele • COMPLEX CHARACTERS- human conditions that are influenced by a combination of genes and environmental factors. • Skin color, height, heart disease
Multiple Alleles • Genes with 3 or more alleles. Example: Blood types, ABO • Multiple alleles often lead to codominance (both traits expressed) or incomplete dominance (an in-between trait is expressed, ie wavy hair).
Blood Types • 4 types • Type A, Type B, Type O, Type AB • A and B are dominant • O is recessive • AO= A blood type • BO=B blood type • AB=genes are CODOMINANT, blood type is AB • Brain Pop –Blood Types
Blood Typing • Complete the squares below to determine the different possible genotype combinations for offspring: Make Punnett Squares for these as well: Mom—OO Dad—AB Mom—AA Dad—BB Mom—AA Dad—AO Mom—BB Dad AO Mom—AB Dad OO Mom—AO Dad BO Father’s Genotype Mother’s Genotype
X-Linked Traits • X-Linked traits are traits found on the X-chromosome and often only males will exhibit the recessive trait (since they don’t have a counterpart on the Y to dominate it). • Colorblindness is an X-linked trait and therefore more common in males • X-Linked Practice!
Single Allele Traits • More than 200 human traits are controlled by a single allele. • Huntington’s Disease is a single allele, dominant, disease.
Genetic Screening and Genetic Disorders • Many people seek GENETIC SCREENING before having children. • GENETIC SCREENING is an examination of a person’s genetic makeup to see what traits may be passed on to an offspring. • GENETIC COUNSELING is when a person seeks professional, medical guidance about the risks of passing on traits to children • AMNIOCENTESIS is a procedure to test the amniotic fluid during pregnancy to analyze fetal DNA and check for genetic disease.
Gene Therapy • In your own words, what is gene therapy? • Gene therapy cures blindness?
Genetic Disorder Powerpoints and Presentations Choose a disorder and complete the presentation. You may choose one from below or find your own. • Huntington’s Disease • Alexander Disease • Alzheimer’s • Autism • Barth Syndrome • Cerebral Palsy • Cleft Palate • Cystic Fibrosis • Down Syndrome • Hemophilia • Marfan Syndrome • Long Q-T Syndrome • Progeria • Sickle Cell Anemia • Spina Bifida • Williams Syndrome