Human Genetics

Breaking Down the Definitions Honors 1.Sex chromosome 2.Autosome 3.Sex-linked trait 4.Linked gene 5.Chromosome map 6.Map unit 7.Germ-cell mutation 8.Somatic-cell mutation 9.Lethal mutation 10.Deletion 11.Inversion 12.Translocation 13.Nondisjunction 14.Point mutation 15.Substitution 16.Frameshift mutation 17.Insertion mutation 18.Pedigree 19.Carrier 20.Genetic disorder 21.Polygenic 22.Complex character 23.Multiple allele 24.Sex-influenced trait 25.Huntington’s Disease 26.Amniocentesis 27.Chorionic villi sampling 28.Genetic counseling 29.Gene therapy

Breaking Down the Definitions Reg. Bio 1.Karyotype 2.Sex chromosome 3.Autosome 4.Pedigree 5.Sex linked gene 6.Nondisjunction 7.DNA fingerprinting 8.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.

Punnett Squares with Sex Chromosomes

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) Germ-Cell In the Gametes Do not affect the organism but can be passed on to offspring Somatic-Cell In the body cells Can affect the organism, but are not passed on Lethal Causes death; usually before birth

Chromosome Mutations CHROMOSOME MUTATIONS are changes in the structure of a chromosome or the loss/gain of an entire chromosome Loss of a piece of a chromosome Deletion A chromosomal segment breaks off, flips backwards, and reattaches Inversion A piece of one chromosome breaks off and reattaches to another chromosome Translocation A chromosome fails to separate during meiosis, therefore one gamete receives an extra copy and one gamete receives no copy Nondisjunction

Flapbook—4 types of Chromosome Mutations!

Gene Mutations Point Mutation Substitution, addition, or removal of a single nucleotide (letter) Change occurs within a single gene Substitution One nucleotide replaces another If this occurs in a codon, the amino acid can be changed Frameshift Mutation Loss of a nucleotide resulting in the incorrect grouping of codons, making all the amino acids change Insertion Mutation One or more nucleotides are added to a gene Can also cause a Frameshift mutation

Mutation Video Clip Give an example of an addition Give an example of a deletion

Flapbook Gene Mutations!

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: 1.Which 2-3 traits are the most common? 2.Which 2-3 traits are the least common? 3.Which gene of yours did you find to be common? 4.Which gene of yours did you find to be uncommon?

Pedigree Practice

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: AB A B Father’s Genotype Mother’s Genotype Make Punnett Squares for these as well: 1.Mom—OO Dad—AB 2.Mom—AA Dad—BB 3.Mom—AA Dad—AO 4.Mom—BB Dad AO 5.Mom—AB Dad OO 6.Mom—AO Dad BO

Codominance, ABO practice

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 DisordersGenetic 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

A Royal Case Study