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Sex Linked Inheritance: (why females are superior to males) (just kidding) (no, but seriously) (ok, I am kidding) (or am I?)

Sex Linked Inheritance:

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Sex Linked Inheritance:. (why females are superior to males) (just kidding) (no, but seriously) (ok, I am kidding) (or am I?). Warm Up. What % probability will a child be born a male? Female? How could we set up a punnett square to show this?. Cornell Notes. Read pages 170-171 - PowerPoint PPT Presentation

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Page 1: Sex Linked Inheritance:

Sex Linked Inheritance:(why females are superior to males)

(just kidding)(no, but seriously)(ok, I am kidding)

(or am I?)

Page 2: Sex Linked Inheritance:

Warm Up

• What % probability will a child be born a male? Female?

• How could we set up a punnett square to show this?

Page 3: Sex Linked Inheritance:

Cornell Notes

• Read pages 170-171• In the margin of your

paper, define the bold terms.

• In the large portion of your paper, discuss 3 main points.

• On the bottom, summarize in 3 sentences what you read.

Page 4: Sex Linked Inheritance:

The difference between males and females.

• Females have 2 X chromosomes.

• They always give one X to their offspring.

• The X chromosome has more information than the Y. That’s why females are superior to males.

• Males have 1 X chromosome and 1 Y chromosome.

• They can give either to offspring.

Page 5: Sex Linked Inheritance:

Human Genome

Autosomes (1 – 22)

Sex Chromosomes(X and Y)

Page 6: Sex Linked Inheritance:

X Y

Page 7: Sex Linked Inheritance:

Human Y-chromosome

SRy locus

Males have sperm cells which may have an X chromosome or a Y chromosome. Male gametes (sperm) determine the gender of the offspring when the egg is fertilized.

Page 8: Sex Linked Inheritance:

Punnett Square to determine gender.

• A male gamete XY chromosomes fertilizes the egg (XX).

• What is the chance that the offspring will be female?

Page 9: Sex Linked Inheritance:

Punnett Square to determine gender.

• A male gamete XY chromosomes fertilizes the egg.

X Y

X

X

Page 10: Sex Linked Inheritance:

Punnett Square to determine gender.

• A male gamete XY chromosomes fertilizes the egg.

X Y

X

X

XX XYXX XY

Page 11: Sex Linked Inheritance:

X chromosomes have genes that Y chromosomes don’t.

• X Chromosomes can be carriers of certain recessive traits. In females, the other X probably does not have the trait and can over rule the recessive diseased trait.

BaldnessColor BlindnessDuchenne Muscular DystrophyAdrenoleukodystrophyFragile X Syndrome

Page 12: Sex Linked Inheritance:

Punnett Square to determine gender.

• A carrier female for colorblindness, marries a normal man.

• Will their children be color blind?

• B= normal• b= color blind• Y’s don’t have the trait.

XB Y

XB

Xb

Page 13: Sex Linked Inheritance:

Punnett Square to determine gender.

• A carrier female for colorblindness, marries a normal man.

• Will their children be color blind?

• B= normal• b= color blind• Y’s don’t have the trait.

XB Y

XB

Xb

XBXB XBY

XBXb XbY

Page 14: Sex Linked Inheritance:

Punnett Square to determine gender.

• Normal Female• Normal Male• Carrier Female (isn’t

colorblind)• Colorblind Male

XB Y

XB

Xb

XBXB XBY

XBXb XbY

Page 15: Sex Linked Inheritance:

Inheritance patterns:• Sex-linked recessive conditions

The disease is never passed from father to son.

Males are much more likely to be affected than females.

• All affected males in a family are related through their mothers.

Trait or disease is typically passed from an affected grandfather, through his carrier daughters, to half of his grandsons.

Page 16: Sex Linked Inheritance:

PRACTICEOn your pink sheet of paper… practice the following…