Bellwork: 4/18 Put your phone up  Week 4/15 - 4/19 Quiz Day – you have 2 min to look over notes

Today: Quiz Part 6 Notes Pedigree Practice Video

Materials Unit Book Pedigree Packet

This Week: Monday: Pt. 5 Notes & Practice Tues/Wed: Sex-Link Quick Lab & Movie Thursday: Quiz, Pt. 6 Notes, & Practice Friday: Practice & White Board Practice

Next Week: Monday: Study Guide (maybe Kahoot) Tues/Wed: Test Thursday: Presentations Friday: Presentations

Homework Genetics Project Unit 6 Test Study Guide & All Late Work Due 4/24 at 11:59pm Unit 6 Test Period 4 & 6: April 23 Period 5 & 7: April 24 Study Guide & All Late Work

Unit VI: Mendelian Genetics

Part 6: Human Genetics

Human Genetics We can follow specific genetic traits by examining family members across generations through pedigree analysis More recently, genetic testing has allowed inheritance of genetic diseases to be determined

Pedigree Analysis Pedigree Analysis – family tree that records & traces the occurrence of a trait in a family through several generations

Symbols Used Symbols used: Squares – males Circles – females Horizontal Line – indicates a mating event Each level of the tree represents a generation

Symbols Used Symbols used: Vertical line - represents offspring produced Offspring are listed in birth order from left to right Shaded symbols indicate individuals with the trait being traced

Solving Pedigree Analysis Problems If parents without trait have offspring with trait, parents carriers Trait observed in every generation – dominant trait Exception: if trait recessive & both parents have it then all the children in the next generation have it Knowing these general rules, identify individuals where the genotypes can be determined based on pedigree Go back & identify genotypes that are incomplete. For example, you know at least one allele is dominant but unable to determine second allele Indicate with a ?

Sample Problem The ability to taste phenylthiocarbamide (PTC) is controlled by a single dominant allele (T). A woman non-taster married a man taster & they had three children, two boy tasters & a girl non-taster. All the grandparents were tasters. Create a pedigree for this family for this trait. (Solid symbols should signify non- tasters (tt))

Genetic Testing Sequencing the human genome has open new opportunities for genetic testing Genetic Testing involves examining your DNA for changes or alterations that could cause illness or disease Tests are done on collected blood or other tissues

Genetic Testing Used for: Identifying genetic diseases in developing fetuses Identifying if potential parents are carriers of a genetic disease Screen newborns for genetic diseases Screening embryos produced in vitro fertilization before implantation Testing adults for genetic diseases before symptoms arise Making a definitive diagnosis for an individual who shows disease symptoms

Genetic Disorders Arise when mutations occur and are passed down to subsequent generations

Genetic Disorders Classified based on where mutation occurred Two types Autosomal – mutation associated with chromosomes 1-22 Sex-linked – mutation associated with sex chromosome

Autosomal Dominant Disorder Characteristics: Every individual with condition will have a parent with condition

Autosomal Dominant Disorder Marfan Syndrome: Cannot make protein called fibrillin – weakens body structure Phenotype: Tend to be tall Have long fingers Long arms Weakened aorta – main blood vessel from heart

Autosomal Dominant Disorder Achondroplasia: Form of dwarfism Individuals seldom reach 5 ft. in height Disorder of bone growth Most cases, result of spontaneous mutation Symptoms Short stature Bowed legs Disproportionate large head to body size

Autosomal Recessive Disorder Characteristics: Individual with the condition can have one, two, or neither parent exhibit the condition If homozygous recessive – person will have the condition If heterozygous – the individuals are carriers

Autosomal Recessive Disorder Methemoglobinemia: Defective enzyme diaphorase Relatively harmless disorder Results from accumulation of methemoglobin in the blood Hemoglobin, oxygen carrying protein in blood gives blood its red color Hemoglobin slowly converted to methemoglobin (has bluish color) Diaphorase converts methemoglobin back to hemoglobin

Alteration in Chromosome Number Nondisjunction - occurs when either homologous chromosomes or sister chromatids fail to separate during anaphase of meiosis or mitosis

Think Draw a diagram of meiosis & show what happens when the homologous chromosomes fail to separate.

Nondisjunction & Meiosis

Example of Nondisjunction Down Syndrome Cells have 3 copies of chromosome 21 rather than 2

Karyotype of Down Syndrome

Other Examples of Nondisjunction Klinefelter Syndrome - XXY Phenotype – male; sterile; breast enlargement Supermale – XYY Phenotype - high level of testosterone; tall; severe acne; tends to have increase violence