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7.4 Human Genetics and Pedigrees
Set up Cornell Notes on pg. 87 Topic: 7.4 Human Genetics and Pedigrees Essential Questions: 1. NO EQ 7.4 Human Genetics and Pedigrees 2.1 Atoms, Ions, and Molecules KEY CONCEPT A combination of methods is used to study human genetics.
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Autosomal Dominant Pedigree
86 Autosomal Recessive Pedigree Autosomal Recessive Pedigree #2
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KEY CONCEPT A combination of methods is used to study human genetics.
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Inheritance of many human traits is complex
The basic principles of genetics are the same in all sexually reproducing organisms. Inheritance of many human traits is complex Single-gene traits are important in understanding human genetics. Ex: widow’s peak Widow’s peak
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A pedigree is a chart for tracing genes in a family.
Phenotypes are used to infer genotypes Please copy on Pg. 87 Pedigree Key: Boxes = males Circles = females Shaded = they show the trait White = does not show trait Half shaded = carrier (Carrier= Only for recessive disorders) Offspring is dead=
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How many females are in this family?
How many carriers? How many children were in generation two? How many offspring in generation three are affected by the trait? Pg. 86 top margin Generation 1 Generation 2 Generation 3 Generation 4
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How many females are in this family? 11 How many carriers? 7
How many children were in generation two? 5 How many offspring in generation three are affected by the trait? 2 Generation 1 Generation 2 Generation 3 Generation 4
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In pedigrees that show Autosomal Dominant Traits/Disorders- Many family members will be shaded
Widow’s peak No Widow’s peak
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On the top of pg. 86, please create this pedigree and answer the following questions. Always include GENOTYPE when possible: Jamie and Joe married in Joe was homozygous dominant for a Widow’s Peak, while Jamie did not have a Widow’s Peak. They had two children: A son named Kyle and a daughter named Marie. Kyle married a woman who had no Widow’s Peak. Marie never married. Kyle and his wife had three children: Two boys and a girl. Do Kyle and Marie have Widow’s Peaks? What percent of Kyle’s children can we expect to have Widow’s Peaks? What percent of Kyle’s children can we expect to have NO Widow’s Peaks?
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Joe Jamie WW ww Marie Kyle
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Joe Jamie WW ww WW x ww 100% Ww Marie Kyle Ww Ww Yes, Kyle and Marie have Widow’s Peaks
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? ? ? Joe Jamie WW ww WW x ww 100% Ww Marie Kyle ww Ww Ww Ww x ww
50% Ww and 50% ww ? ? ? Yes, Kyle and Marie have Widow’s Peaks 50% should have Widow’s Peaks 50% should have NO Widow’s Peaks
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In pedigrees that show Autosomal Recessive Traits/Disorders only a few organisms, will be shaded in.
Only will show up if heterozygotes mate, may skip a few generations before reappearing. REMEMBER: if it is an autosomal recessive disorders CARRIERS will be present and must be half shaded in.
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On the middle of pg. 86, Fill in the genotypes of this incomplete pedigree. Shade if necessary.
Albinism is an autosomal RECESSIVE disorder aa
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You need to complete two Punnet sqs. to find out the answer
Aa or AA? aa aa aa aa
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AA x aa 100% Aa? Aa x aa 50% Aa--50% aa Aa or AA? aa aa aa aa
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AA x aa 100% Aa? Aa x aa 50% Aa--50% aa Aa or AA? aa aa aa aa
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Aa aa aa Aa Aa Aa aa aa
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Can use previous Punnett Sq to answer this
Aa aa Aa or AA? aa Aa Aa Aa aa aa
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Aa aa Aa aa Aa Aa Aa aa aa Aa
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AA x aa 100% Aa? Aa x aa 50% Aa--50% aa Aa aa Aa or AA? Aa aa Aa Aa Aa aa aa Aa Anyway to know for sure?
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Aa aa Aa or AA ? Aa aa Aa Aa Aa ? ? aa aa Aa
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SHADE AS NECESSARY Aa aa Aa or AA ? Aa aa Aa Aa Aa ? ? Aa or AA aa aa Aa
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SHADE AS NECESSARY Aa aa Aa or AA ? Aa aa Aa Aa Aa ? ? Aa or AA aa aa Aa
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Bottom of Pg. 86 Mary and Joe were married in Both Mary and Joe were carriers for a fatal recessive disorder called Cystic Fibrosis. They had three children: A son named Pete who was a carrier, a son named Charles who was not a carrier and did not have the disease, and a girl named Isabel who died from Cystic Fibrosis. Pete married a woman who was homozygous dominant. Pete and his wife are worried about having a child with Cystic Fibrosis. Should they worry? What are the chances of any of their children having Cystic Fibrosis? Carriers?
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Joe Mary Ff Ff Isabel Charles Pete Ff FF FF ff ?
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Joe Mary Ff Ff Isabel Charles Pete Ff FF FF ff FF x Ff O%- No chance of any of their children having the disorder 50% will be carriers They DO NOT need to be worried about having a child with CF
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7.4 Human Genetics and Pedigrees: Sex-linked traits
Set up Cornell Notes on pg. 89 Topic: 7.4 Human Genetics and Pedigrees Essential Questions: 1. NO EQ 7.4 Human Genetics and Pedigrees: Sex-linked traits 2.1 Atoms, Ions, and Molecules
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Females can carry sex-linked genetic disorders.
Males (XY) express all of their sex linked genes. Expression of the disorder depends on which parent carries the allele and the sex of the child. X Y
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In pedigrees showing Sex-linked traits: More males will be shaded in because they do not have another X to mask the disorder Ex: Color blindness males females
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X-linked Color Blindness- Recessive XMXM= Normal XMXm= carrier
XmXm= CB XMY= Normal XmY= CB XmY XMXm XMXm XMXm XMXm XMY XmY On pg. 88, Fill in the genotypes of this incomplete pedigree. Shade if necessary. ? XmY XmY XMXM or XMXm
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A karyotype is a picture of all chromosomes in a cell.
X Y
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Karyotypes can show changes in chromosomes.
deletion of part of a chromosome or loss of a chromosome large changes in chromosomes extra chromosomes or duplication of part of a chromosome
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In down syndrome a person has an extra copy of chromosome 21.
In Klinefelter’s syndrome a male has an extra X (XXY).
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Pedigree Practice Worksheet
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How many males have hemophilia?
How many females? How many females have hemophilia? 5 4 6 7 8 9 10 11 12 13 14 15 16
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How many males have hemophilia? 3
How many females? 8 How many females have hemophilia? 2 5 4 6 7 8 9 10 11 12 13 14 15 16
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How many marriages are there?
5 4 6 7 8 9 10 11 12 13 14 15 16
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How many marriages are there? 3
5 4 6 7 8 9 10 11 12 13 14 15 16
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How many children did the first couple have?
How many children did the third couple have? How many generations are there? How many members in the 4th generation? 5 4 6 7 8 9 10 11 12 13 14 15 16
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How many children did the first couple have? 2
How many children did the third couple have? 7 How many generations are there? 4 How many members in the 4th generation? 7 5 4 6 7 8 9 10 11 12 13 14 15 16
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Determine the GENOTYPES for as many of the family members as possible.
Now the harder part… Determine the GENOTYPES for as many of the family members as possible. You can find all genotypes except for one. 5 4 6 7 8 9 10 11 12 13 14 15 16
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Fill in the OBVIOUS genotypes first (the affected individuals)
5 4 6 7 8 9 10 11 12 13 14 15 16
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Fill in the OBVIOUS genotypes first the affected individuals
The non-affected males XnXn 5 4 6 7 8 9 XnY 10 11 12 13 14 15 16 XnY XnY XnXn
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You may need to complete more than one!!!!!
Then start at the top, and using Punnett Sqs. Determine the possible genotypes of the female offspring in each generation. You may need to complete more than one!!!!! XnXn 5 4 XNY 6 7 8 9 XNY XnY 10 11 12 13 14 15 16 XnY XnXn XnY XNY XNY
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/ 100% XNY XnXn XNY XnXn XNXn 5 4 XNXn XNXn XNY 6 7 8 9 XNY XnY 10 11
12 13 14 15 16 XnY XnXn XnY XNY XNY
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/ 50% XNY XNXn XNY XnXn XNXn 5 XNXN 4 XNXn XNXn XNY 6 7 8 9 XNY XnY 10
11 12 13 14 15 16 XnY XnXn XnY XNY XNY
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? XNY XnXn 5 4 XNXn XNXn XNY XNXn or XNXN 6 7 8 9 XNY XnY 10 11 12 13
14 15 16 XnY XnXn XnY XNY XNY
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You need to complete 2 test crosses to figure out what mom is.
XNY XnXn 5 4 XNXn XNXn XNY You need to complete 2 test crosses to figure out what mom is. 6 7 8 9 ? XNY XNXn or XnY XNXN 10 11 12 13 14 15 16 XnY XnXn XnY XNY XNY
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/ and / ? XnY XNXn XNY XnXn 5 XnY 4 XNXN XNXn XNXn XNY 6 7 8 9 XNY
XNXn or XnY XNXN 10 11 12 13 14 15 16 XnXn XnY XnY XNY XNY
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/ and / ? XnY XNXn XNY XnXn 5 XnY 4 XNXN XNXn XNXn XNY 6 7 8 9 XNY
XNXn or XnY XNXn XNXN 10 11 12 13 14 15 16 XnXn XnY XnY XNY XNY
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SHADE THE CARRIERS IN AS NECESSARY
XNY XnXn 5 4 XNXn XNXn XNY 6 7 8 9 ? XNY XNXn or XnY XNXn XNXN 10 11 12 13 14 15 16 XNXn XnY XnXn XnY XNY XNY XNXn
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Now answer the rest of the questions.
XNY XnXn Now answer the rest of the questions. 5 4 XNXn XNXn XNY 6 7 8 9 ? XNY XNXn or XnY XNXn XNXN 10 11 12 13 14 15 16 XnY XNXn XnY XnXn XNY XNY XNXn
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Pedigree Worksheet Complete the back by yourself for homework Part B NOT SEX-LINKED (no XX or XY) Determine if black fur or white fur is dominant or recessive Use pencil in case you make mistakes Part C Draw your own pedigree for the SEX-LINKED disorder Outline each shape following the color-coding key
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Who Gets the Money Purpose: To solve a mystery involving genetics Background: Mr. and Mrs. John Jones dies in a tragic farm accident when the tractor they were riding on rolled over in a ditch. Authorities found one million dollars hidden in a feed bin in the chicken coop. The couple is known to have a son, from whom they are estranged. This man is sole heir to the Jones fortune. Procedure: Completes parts one, two, and three to find out who gets the money!
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Who Gets the Money Part I: Dihybrid Cross Part II: Punnett Squares Part II: Sex-linked Traits Blood type: Genotype possibilities
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