“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
MUTATIONMUTATION 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
oneCAPITAL
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 dominanceAlleles (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
Genotype Phenotype (blood group)
IA IA or IAi A
IB IB, or IBi B
IAIB AB
ii O
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
XBXB normal female XBXb carrier female XbXb affected female XBY normal male XbY affected male
Sex linked inheritance Dominant Dominant gene on X chromosome Affected males pass to all daughters and none of
their sons Genotype= XAY
If the mother = X- linked dominant trait & is homozygous (XAXA) all children will be affected
If Mother heterozygous (XAXa) 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 PedigreeLook 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 PedigreeLook for: Skips in generation Unaffected parents can
have affected children Affected person must be
homozygous Males and females
affected equally
Sex linked Dominant pedigreesLook 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?
What kind of inheritance pattern?