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7.4 Human Genetics and Pedigrees Set up Cornell Notes on pg. 81 Topic: 7.4 Human Genetics and Pedigrees Essential Questions: 1. NO EQ 2.1 Atoms, Ions,

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Presentation on theme: "7.4 Human Genetics and Pedigrees Set up Cornell Notes on pg. 81 Topic: 7.4 Human Genetics and Pedigrees Essential Questions: 1. NO EQ 2.1 Atoms, Ions,"— Presentation transcript:

1 7.4 Human Genetics and Pedigrees Set up Cornell Notes on pg. 81 Topic: 7.4 Human Genetics and Pedigrees Essential Questions: 1. NO EQ 2.1 Atoms, Ions, and Molecules 7.4 Human Genetics and Pedigrees KEY CONCEPT A combination of methods is used to study human genetics.

2 7.4 Human Genetics and Pedigrees KEY CONCEPT A combination of methods is used to study human genetics.

3 7.4 Human Genetics and Pedigrees 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

4 7.4 Human Genetics and Pedigrees Boxes = males Circles = females Shaded = they show the trait White = does not show trait Half shaded = carrier (Carrier= Only for recessive disorders) A pedigree is a chart for tracing genes in a family. Pedigree Key: Phenotypes are used to infer genotypes Please copy on Pg. 80

5 7.4 Human Genetics and Pedigrees 1.How many females are in this family? 2.How many carriers? 3.How many children were in generation two? 4.How many offspring in generation three are affected by the trait? Generation 1 Generation 2 Generation 3 Generation 4 Pg. 80

6 7.4 Human Genetics and Pedigrees 1.How many females are in this family? 11 2.How many carriers? 7 3.How many children were in generation two? 5 4.How many offspring in generation three are affected by the trait? 2 Generation 1 Generation 2 Generation 3 Generation 4

7 7.4 Human Genetics and Pedigrees Widow’s peak No Widow’s peak Autosomal Dominant Trait- Many family members will show the trait in the pedigree

8 7.4 Human Genetics and Pedigrees Jamie and Joe married in 1912. 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? On pg. 81, please create this pedigree and answer the following questions:

9 7.4 Human Genetics and Pedigrees Joe Jamie Kyle Marie LL ll Ll ll ? ? ? LL x ll 100% Ll Ll x ll 50% Ll and 50% ll 1.Yes, Kyle and Marie have Widow’s Peaks 2.50% should have Widow’s Peaks 3.50% should have NO Widow’s Peaks

10 7.4 Human Genetics and Pedigrees Autosomal Recessive Disorders will show up if carriers mate, may skip a few generations before reappearing. Only a few, will show the trait/disorder aa On pg. 81, Fill in the genotypes of this incomplete pedigree. Shade if necessary.

11 7.4 Human Genetics and Pedigrees aa On pg. 81, Fill in the genotypes of this incomplete pedigree. Shade if necessary.

12 7.4 Human Genetics and Pedigrees aa Fill in the genotypes. Shade if necessary Aa aaAa aa Aa Aa or AA Prob. AA or Aa Albinism is an autosomal recessive disorder. ? ? ?

13 7.4 Human Genetics and Pedigrees Mary and Joe were married in 1950. 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? Pg. 80

14 7.4 Human Genetics and Pedigrees Joe Mary Pete Isabel Ff ff FF Charles FF ? ?? FF x Ff O%- No chance of any of their children having the disorder 50% will be carriers

15 7.4 Human Genetics and Pedigrees 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

16 7.4 Human Genetics and Pedigrees Sex-linked traits: More males will show their sex-linked traits because they do not have another X to mask the disorder Ex: Color blindness males females

17 7.4 Human Genetics and Pedigrees X-linked Color Blindness- Recessive X M X M = Normal X M X m = carrier X m X m = CB X M Y= Normal X m Y= CB XmYXmY XmYXmY XmYXmY XmYXmY XMYXMY XMXmXMXm XMXmXMXm XMXmXMXm XMXmXMXm X M X M or X M X m ? On pg. 80, Fill in the genotypes of this incomplete pedigree. Shade if necessary.

18 7.4 Human Genetics and Pedigrees A karyotype is a picture of all chromosomes in a cell. X Y

19 7.4 Human Genetics and Pedigrees 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

20 7.4 Human Genetics and Pedigrees 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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