other patterns of inheritance

20
OTHER PATTERNS OF INHERITANCE 1

Upload: micol

Post on 06-Jan-2016

62 views

Category:

Documents


0 download

DESCRIPTION

OTHER PATTERNS OF INHERITANCE. Alleles for different traits are distributed to sex cells (& offspring) independently of one another. Law of Independent Assortment. Sex-Linked Traits. Trait determined by a gene on a sex chromosome (usually X ). Examples: Colorblindness Hemophilia - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: OTHER PATTERNS OF INHERITANCE

OTHER PATTERNS OF INHERITANCE

1

Page 2: OTHER PATTERNS OF INHERITANCE

Alleles for Alleles for differentdifferent traits are traits are distributed to distributed to sex cellssex cells (& (& offspring) offspring) independentlyindependently of of one another.one another.

2

Page 3: OTHER PATTERNS OF INHERITANCE

Trait determined by a gene on a sex chromosome (usually X).

Examples:Colorblindness

HemophiliaMuscular Dystrophy

Page 4: OTHER PATTERNS OF INHERITANCE

*Females must receive 2 affected X’s in order to express the trait.•Females with only 1 affected X are carriers.•Males that receive one X from mother expresses the trait.

Page 5: OTHER PATTERNS OF INHERITANCE

Cross a colorblind mother with a father who has normal vision: Give the genotypic and phenotypic ratios.

Key: Key: XXcXcXc = colorblind mother XY = colorblind mother XY = normal vision fatherCross: XcXc (x) XY

5

Xc Xc

X

Y

Genotypic Ratio:

Phenotypic Ratio:

Answer on next slide…

Page 6: OTHER PATTERNS OF INHERITANCE

SEX-LINKEDSEX-LINKED

6

XcXXcX

XcYXcY

XcXXcX

XcYXcY

XX

YY

XcXcXc

Key: XX = female XY = maleCross: XcXc (x) XY

Genotypic Ratio:2:4 XcX 2:4 XcY

Phenotypic Ratio:2:4 Carrier Female2:4 Colorblind Male

Page 7: OTHER PATTERNS OF INHERITANCE

“Many genes” ; Many traits are controlled by more than one gene; have a variety of choices for expression.

Ex: _hair color, eye color, skin tone___

7

Page 8: OTHER PATTERNS OF INHERITANCE

Genes that have more than 2 alleles

Ex: blood group.

There are 3 possible alleles for this gene.

8

i

ii

Page 9: OTHER PATTERNS OF INHERITANCE

Cross a female who is Type AA with a male who is Type O (ii): Give the genotypic and phenotypic ratios.

Key: Key: AAAA = mother ii = mother ii = fatherCross: AA x ii

9

A A

i

i

Genotypic Ratio:

Phenotypic Ratio:

Answer on next slide…

Page 10: OTHER PATTERNS OF INHERITANCE

BLOOD TYPEBLOOD TYPE

10

AiAi

AiAi

AiAi

AiAi

ii

ii

AAA

Key: AA = female ii = maleCross: XcXc (x) XY

Genotypic Ratio:4:4 Ai

Phenotypic Ratio:4:4 Type A Blood

Page 11: OTHER PATTERNS OF INHERITANCE

INCOMPLETE DOMINANCEINCOMPLETE DOMINANCE Neither allele has “complete”

dominance over the other; heterozygous phenotype is a blend of the 2 homozygous phenotypes

Ex: snapdragons R = red W = white RW = pink

11

Page 12: OTHER PATTERNS OF INHERITANCE

Cross a red (RR) snapdragon with a White (WW) snapdragon. Give the genotypic and phenotypic ratios.

Key: R = red flower WKey: R = red flower W = white flower

Cross: RR x WW

12

W W

R

R

Genotypic Ratio:

Phenotypic Ratio:

Answer on next slide…

Page 13: OTHER PATTERNS OF INHERITANCE

INCOMPLETE DOMINANCEINCOMPLETE DOMINANCE

13

RWRW

RWRW

RWRW

RWRW

RR

RR

WWW

Key: R = red W = whiteCross: RR x WW

Genotypic Ratio:0RR: 4RW: 0WW

Phenotypic Ratio:0 Red: 4 Pink: 0 White

Page 14: OTHER PATTERNS OF INHERITANCE

INCOMPLETE DOMINANCEINCOMPLETE DOMINANCE

14

Practice: Cross a pink snapdragon with a red snapdragon. Give the expected phenotypic and genotypic ratios.

Key: __________________

Cross: _________________

Genotypic Ratio: ________________________

Phenotypic Ratio: ________________________

Page 15: OTHER PATTERNS OF INHERITANCE

INCOMPLETE DOMINANCEINCOMPLETE DOMINANCE

15

Practice: Cross a pink snapdragon with a red snapdragon. Give the expected phenotypic and genotypic ratios.

Key: R = red W = white RW = pink

Cross: _RW x RR__

Genotypic Ratio: __2RR: 2RW: 0WW__

Phenotypic Ratio: __2 red: 2 pink: 0 white_

RR

WW

RR RR

RRRR RRRR

RWRW RWRW

Page 16: OTHER PATTERNS OF INHERITANCE

CODOMINANCECODOMINANCE Codominance – Both alleles share

dominance and are always expressed if present.

Ex: In chickens B = black feathers W = white feathers BW = black AND white feathers

16

X

Page 17: OTHER PATTERNS OF INHERITANCE

Cross a black (B) rooster with a white (W) chicken.

Give the genotypic and phenotypic ratios.Key: B = black feathers WKey: B = black feathers W = white

feathersCross: BB x WW

17

W W

B

B

Genotypic Ratio:

Phenotypic Ratio:

Answer on next slide…

Page 18: OTHER PATTERNS OF INHERITANCE

CODOMINANCECODOMINANCE

18

BWBW

BWBW

BWBW

BWBW

BB

BB

WWW

Key: B = black W = whiteCross: BB x WW

Genotypic Ratio:0BB: 4BW: 0WW

Phenotypic Ratio:0 black: 4 black and white: 0 white

Page 19: OTHER PATTERNS OF INHERITANCE

CODOMINANCECODOMINANCE

19

Practice: Cross two black and white feathered chickens. Give the expected phenotypic and genotypic ratios of the offspring.

Key: __________________

Cross: _________________

Genotypic Ratio: ________________________

Phenotypic Ratio: ________________________

Page 20: OTHER PATTERNS OF INHERITANCE

CODOMINANCECODOMINANCE

20

Practice: Cross two black and white feathered chickens. Give the expected phenotypic and genotypic ratios of the offspring.

Key: B = black W = white

BW = black and white

Cross: _BW x BW__

Genotypic Ratio: __1BB: 2BW: 1WW_

Phenotypic Ratio: _1 black: 2 black and white: 1 white_

BB

WW

BB WW

BBBB BWBW

BWBW WWWW