Part 4 What is a PEDIGREE A chart used to trace traits throughout a family Parts of the chart Circle females Squares males Halffilled inDotted carrier Have the gene but do not show signs of it ID: 776438
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Slide1
Pedigrees and Sex linked Traits
Part 4
Slide2What is a PEDIGREE
A chart used to trace traits throughout a family
Parts of the chart
Circle = females
Squares = males
Half-filled in/Dotted = carrier
Have the gene but do not show signs of it
Filled-in = affected
Have both the gene and symptoms of that trait
Slide3Pedigrees - A chart used to trace traits through generations of a family-
Slide4How can a pedigree trace a trait ?
Circle = femalesSquares = malesHalf-filled in= carrier – they have the gene but do not show signs of the disorderHeterozygous – they can pass it on to their offspringFilled-in = affectedHave both the gene and symptoms of that trait
Slide5Bellwork: 10/30
The following pedigree shows cystic fibrosis
1.Does anyone in generation 3 have cystic fibrosis?2. Does generation 3 have any carriers?3. How many female offspring did the first generation have?How many of the offspring in generation 2 were affected?4. Describe individual 4 in generation 3
Ifc:
Slide6Sex chromosomes and sex linked disorders
Slide7How is the sex of offspring determined?
Sex chromosomes – determine the sex of an individualY or XMales = X and Y - XYFemale = X and X- XX
Slide8Which parent determines the sex of the offspring?
XY
male
X
Y
XX
Female
X
X
It is the male that determines the sex of the offspring.
Slide9What are Sex-Linked Traits?
Traits controlled by genes located on sex chromosomes (X or Y)Most are on X chromosomeTraits on the sex chromosomes are passed on differently than traits on the rest of the chromosomes.
Slide10What are sex linked disorders – a disease or trait on the sex chromosomes
XX - female can be a carrier or have the trait if she has the gene on both XY male – if it is on the x chromosome, they only need 1 allele to get the disorder.They show up more in males because they only need one gene to get it and females need both.
Slide11Red-green color blindness
Can not distinguish red from green.
Normal red-green
Red-green colorblind
Slide12What a red-green colorblind person would see
Normal
Red-green colorblind
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