“Bell Ringer” for 4/6  What are the 2 types of mutations that you see below? Which is more detrimental and why? Correct sequence: A T T C G T G A A Mutation A: A T T T G C G A A Mutation B: A T T G T G A A  Your Monster Lab and your index card (make sure your name is on it!) will be collected in 10 min. Make sure you are ready when time is called!

Study Guide  DNA and RNA: Know the base-pairing rules Who discovered them? How?  Transcription and Translation What happens and where they occur  Mutations Identify types, what causes them  Kayrotypes What are they used for, autosomes vs. sex chromosomes  Pedigrees Demonstrate knowledge of the symbols used Be able to construct one based on descriptions of individual phenotypes Analyze for inheritance pattern  Inheritance Patterns Understand sex-linked, incomplete, and codominant traits Construct Punnett squares to show patterns of inheritance

MUTATION  defined as:  can be caused by errors in _________, _____________, ____________, or by _________________ change in the DNA sequence replication Transcription External agents, or mutagens Cell division

Mutations Review Reproductive cells (eggs/sperm)  Will be passed down to offspring Body (somatic) cells  Will NOT be passed down to offspring  Base-pair mutations A change caused by one to few bases on a DNA or RNA strand  Chromosomal mutations A change caused by larger scale chromosomal changes (involving alteration of several hundred-several thousand base-pairs)

What kind of mutation? What do you see happening? Point Mutation

What type of mutation? How is this different than a point mutation? How is it similar?

Chromosomal mutations  When there are changes that affect the chromosome, it is considered a chromosomal mutation. Part of a chromosome is broken off and lost Break and rejoin incorrectly  Nondisjunction

Nondisjunction What do you notice about the daughter cells that are produced?

Pedigree basics

Rewiew  What is genotype?  How about phenotype?  What is an allele?

Autosomal Dominant Inheritance  Alleles: Dominate traits are represented by ____________ letters. Affected individuals have to carry at least ___ dominant gene (heterozygous or homozygous)  Chance of Inheritance: Passed onto __________________________  Parents: Every person affected must have at least 1 parent with the trait  Generations: Does not skip generations one CAPITAL Males and females EQUALLY

Autosomal Recessive Inheritance  Alleles: Represented by _______________ letters Unaffected parents (heterozygous) can produce affected offspring (if they get both recessive genes: homozygous)  Chance of inheritance: Inherited by both males and females  Parents: If _____ parents have the trait then all offspring will also have the trait. The parents are both homozygous.  Generations: __________________________ Lower case both Can skip generations

 Review Homozygous Heterozygous Genotype Phenotype

Incomplete dominance Alleles ( See page 322 in text) Use ___________ capital letter for both alleles, but one is distinguished by __________ _______________ individuals will have a phenotype that is an intermediate between both alleles for a trait. Black + white = grey The same Adding ‘ heterozygous

Incomplete dominance

Co- dominance  Alleles: Use the SAME capital letter to represent the trait, distinguish the alleles by: ________________________________ Heterozygous individuals will have a phenotype that distinctly shows ________ alleles.  Think “dairy cow”  See page 331 in your books. Using different capital letters, superscript to the one for the trait both

Co- dominance GenotypePhenotype (blood group) I A I A or I A iA I B I B, or I B iB IAIBIAIB AB iiO How many alleles do you see for determining blood type?

Sex linked inheritance  Genes are carried on the sex chromosomes (X or Y)  Sex-linked notation X B X B normal female X B X b carrier female X b X b affected female X B Y normal male X b Y affected male

Sex linked inheritance Dominant  Dominant gene on X chromosome  Affected males pass to all daughters and none of their sons Genotype= X A Y  If the mother = X- linked dominant trait & is homozygous (X A X A ) all children will be affected  If Mother heterozygous (X A X a ) 50% chance of each child being affected

Sex linked Inheritance Recessive  Gene located on the X chromosome  More males than females affected (males inherit X from mother)  Females can only inherit if the father is affected and mother is a carrier (hetero) or affected (homo)  An affected female will pass the trait to all her sons Daughters will be carriers if father is not affected  Males cannot be carriers  Can skip generations  E.g. colour blindness, haemophilia, Duchene muscular dystrophy

Autosomal Dominant Pedigree Look for:  Trait in every generation Once leaves the pedigree does not return  Every person with the trait must have a parent with the trait  Males and females equally affected

Autosomal Recessive Pedigree Look for:  Skips in generation  Unaffected parents can have affected children  Affected person must be homozygous  Males and females affected equally

Sex linked Dominant pedigrees Look for:  More males being affected  Affected males passing onto all daughter (dominant) and none of his sons  Every affected person must have an affected parent

Sex linked recessive pedigrees  More males being affected  Affected female will pass onto all her sons  Affected male will pass to daughters who will be a carrier (unless mother also affected)  Unaffected father and carrier mother can produce affected sons

What kind of inheritance pattern?