Gene Interaction NS W12

7/21/2019 Gene Interaction NS W12

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Additional Genetic Patterns Additional Genetic Patterns

Mendel’s peasMendel’s peas Other PatternsOther PatternsCompleteCompleteDominanceDominance

Incomplete DominanceIncomplete Dominance

CodominanceCodominance

Lethal AllelesLethal AllelesHierarchy of DominanceHierarchy of Dominance

Two allelesTwo allelesper geneper gene

Mltiple AllelesMltiple Alleles

One gene affectsOne gene affectsone traitone trait

!!Many traits "Pleiotropy#Many traits "Pleiotropy#

Two "or more# genes affectTwo "or more# genes affectone trait "Gene Interactionsone trait "Gene Interactionsand Polygenic Traits#and Polygenic Traits#



Additional Genetic Patterns Additional Genetic Patterns

Mendel’s peasMendel’s peas Other PatternsOther Patterns

Cold not o$ser%eCold not o$ser%egender&specific traitsgender&specific traits

'e(&inflenced traits'e(&inflenced traits

'e(&limited traits'e(&limited traits

)*al contri$tions)*al contri$tionsfrom $oth parentsfrom $oth parents

Cytoplasmic InheritanceCytoplasmic InheritanceGenetic Maternal )ffectGenetic Maternal )ffect

Genomic ImprintingGenomic Imprinting

Trait e(pressed atTrait e(pressed at

same le%el and stagesame le%el and stageof lifeof life

Anticipation Anticipation

+o en%ironmental+o en%ironmentalinflenceinflence

)n%ironmental )ffects)n%ironmental )ffects



Incomplete DominanceIncomplete Dominance

00’ ( 00’00’ ( 00’

Pin- ( Pin-Pin- ( Pin-

Genotypic 0atio,Genotypic 0atio,

Phenotypic 0atio,Phenotypic 0atio,



Mltiple AllelesMltiple Alleles

4 Mltiple alleles, three or more allelesMltiple alleles, three or more allelese(ist for one traite(ist for one trait

"+ote, A diploid indi%idal can only"+ote, A diploid indi%idal can only

carry two alleles at once5# carry two alleles at once5#

6lood Type6lood Type Allele Allele

Type AType A II A A

Type 6Type 6 II66

Type OType O ii




Codominance, +either allele mas-s theCodominance, +either allele mas-s the

other so that effects of $oth alleles areother so that effects of $oth alleles areo$ser%ed in hetero.ygote withoto$ser%ed in hetero.ygote withot

$lending$lending

II A A 11 II66 7 i7 i

II A A and Iand I66 are codominant5are codominant5

II A A and Iand I66 are completely dominant o%er i5are completely dominant o%er i5




PhenotypePhenotype GenotypeGenotype GeneGene

ProdctProdct

Anti$odies Anti$odiesPresentPresent

Type AType A II A AII A A or Ior I A Aii Antigen A Antigen A Anti&6 Anti&6

Type 6Type 6 II66

II66

or Ior I66

ii Antigen 6 Antigen 6 Anti&A Anti&AType A6Type A6 II A AII66 Antigen A Antigen A

andand

Antigen 6 Antigen 6

+either+either

Anti&A nor Anti&A nor

Anti&6 Anti&6

Type OType O iiii nonenone Anti&A Anti&A

andand

Anti&6 Anti&6



Antigens on 0ed 6lood Cells Antigens on 0ed 6lood Cells

IAi IBi

IAIB



Inheritance of 0h /actorInheritance of 0h /actor

PhenotypePhenotype Genotype8Genotype8 GeneGene

ProdctProdct

Anti$odies Anti$odiesPresentPresent

0h Positi%e0h Positi%e 00 or 0r 00 or 0r 0hess Protein0hess Protein +one+one

0h +egati%e0h +egati%e rr rr +one+one +one+onenlessnlesse(posede(posed

8There are mltiple alleles for the 0hess protein8There are mltiple alleles for the 0hess protein"0"0992 02 0::2 02 0;;2 etc5# and all are dominant to the mltiple2 etc5# and all are dominant to the mltiple

alleles for the a$sence of 0hess protein "r alleles for the a$sence of 0hess protein "r 992 r 2 r ::2 r 2 r ;;2 etc5# 52 etc5# 5



Mltiple Alleles and CodominanceMltiple Alleles and Codominance Type A2 0h positi%e ( Type 62 0h negati%eType A2 0h positi%e ( Type 62 0h negati%e

"father is Type O2 0h negati%e# "mother is Type O#"father is Type O2 0h negati%e# "mother is Type O#

Phenotypic 0atio of OffspringPhenotypic 0atio of Offspring



Lethal AllelesLethal Alleles

)(ample, Man( cat)(ample, Man( catMMLL 1 tailless2 lethal in homo.ygote1 tailless2 lethal in homo.ygote

m 1 tailm 1 tail

Tailless male ( Tailless femaleTailless male ( Tailless female



Hierarchy of DominanceHierarchy of Dominance

)(ample, hair crling)(ample, hair crling

''ww 1 wooly '1 wooly 'cc1 crly '1 crly 'wawa1 wa%y s 1 straight1 wa%y s 1 straight

''ww77 ''cc7 '7 'wawa77 ss




Dad Cola%ito has wa%y hair5Dad Cola%ito has wa%y hair5

Mom Cola%ito has crly hair5Mom Cola%ito has crly hair5Their daghter <ean has straight hair5Their daghter <ean has straight hair5

3hat are the e(pected genotypic and3hat are the e(pected genotypic and

phenotypic ratios for their offspring=phenotypic ratios for their offspring=

''ww77 ''cc7 '7 'wawa77 ss




''ww7 '7 'cc7 '7 'wawa77 ss

Dad C ( Mom CDad C ( Mom C

3a%y Crly3a%y Crly

6ons, 3hat is Dr5 C’s genotype=6ons, 3hat is Dr5 C’s genotype=



Pleiotropic )ffectsPleiotropic )ffects

One gene affects manyOne gene affects many

phenotypic characteristicsphenotypic characteristics

Allele Allele '' '’'’

Gene ProdctGene Prodct Hemoglo$in AHemoglo$in A Hemoglo$in 'Hemoglo$in '

Cell 'hapeCell 'hape 0ond0ond 'ic-led nder'ic-led nderlow Olow O

:: tensiontension

0esponse to0esponse to

MalariaMalaria

'scepti$le'scepti$le 0esistant in ''’0esistant in ''’

genotypegenotype



)(ample of Polygenic Inheritance)(ample of Polygenic Inheritance Two genes affecting s-in colorationTwo genes affecting s-in coloration

+m$er of+m$er ofDominantDominant

Alleles Alleles

'-in Color8'-in Color8

"Phenotype#"Phenotype#

GenotypesGenotypes > Pigmentation> Pigmentation

?? 3hite3hite aa$$aa$$ ?&99>?&99>99 Light 6lac-Light 6lac- Aa$$ or aa6$ Aa$$ or aa6$ 9:&:@>9:&:@>

:: Medim 6lac-Medim 6lac- AA$$ or Aa6$ or AA$$ or Aa6$ oraa66aa66

:&B?>:&B?>

;; Dar- 6lac-Dar- 6lac- AA6$ or Aa66 AA6$ or Aa66 B9&@@>B9&@@>

BB Dar-est 6lac-Dar-est 6lac- AA66 AA66 @&>@&>

86ased on a stdy condcted in <amaica586ased on a stdy condcted in <amaica5



Polygenic InheritancePolygenic Inheritance

Medim 6lac- 3omanMedim 6lac- 3oman"mother is white#"mother is white#

E Dar-est 6lac- ManE Dar-est 6lac- Man



Interacting Genes Affecting aInteracting Genes Affecting a

'ingle Characteristic'ingle Characteristic

eg5 '-in coloration in sna-eseg5 '-in coloration in sna-es

One geneOne gene

O 1 orange pigmentO 1 orange pigment

o 1 no orange pigmento 1 no orange pigment

'econd gene'econd gene

66 1 $lac- pigment1 $lac- pigment

$ 1 no $lac- pigment$ 1 no $lac- pigment






Oo 6$ ( Oo 6$Oo 6$ ( Oo 6$

OO 66OO 66 OO6$OO6$ Oo 66Oo 66 Oo 6$Oo 6$

OO 6$OO 6$ OO $$OO $$ Oo 6$Oo 6$ Oo $$Oo $$

Oo 66Oo 66 Oo 6$Oo 6$ o o 66o o 66 o o 6$o o 6$

Oo 6$Oo 6$ Oo $ $Oo $ $ o o 6$o o 6$ o o $ $o o $ $

O6O6 O$O$ o 6o 6 o $o $

O6O6

O$O$

o 6o 6

o $o $






Oo6$ ( Oo6$Oo6$ ( Oo6$

F9 O6 F9 O6

;9 O$$;9 O$$;9 oo6 ;9 oo6

99 oo$$ 99 oo$$



)pistasis)pistasis

4 An allele of one gene mas-s the e(pression of An allele of one gene mas-s the e(pression of

alleles of another gene and e(presses its ownalleles of another gene and e(presses its own

phenotype instead5phenotype instead5

4 Gene that mas-s 1 epistatic geneGene that mas-s 1 epistatic gene

4 Gene that is mas-ed 1 hypostatic geneGene that is mas-ed 1 hypostatic gene

4 Genes that code for en.ymes that areGenes that code for en.ymes that arepstream in a $iochemical pathway sallypstream in a $iochemical pathway sally

e(ert epistasis "standing onJ#5e(ert epistasis "standing onJ#5



0ecessi%e )pistasis0ecessi%e )pistasis

)pistatic gene e(erts its affect with)pistatic gene e(erts its affect with

homo.ygos recessi%e genotype5homo.ygos recessi%e genotype5

eg5 Petal color in $le&eyed Mary plantseg5 Petal color in $le&eyed Mary plants

mm1 magenta2 ww 1white2 3M1 $lemm1 magenta2 ww 1white2 3M1 $le

33

en.yme 9en.yme 9

MM

en.yme :en.yme :

Precrsor 9Precrsor 9 Precrsor :Precrsor :$le anthocyanin$le anthocyanin

colorlesscolorless magenta magenta



Dplicate 0ecessi%e )pistasisDplicate 0ecessi%e )pistasis

Defecti%e prodcts of recessi%e alleles of twoDefecti%e prodcts of recessi%e alleles of twodifferent genes interfere with separate stepsdifferent genes interfere with separate steps

in a $iochemical pathway5in a $iochemical pathway5

eg5 Petal color in hare$ell flowerseg5 Petal color in hare$ell flowers ww 1 white2 $$ 1 white2 3 6 1 $leww 1 white2 $$ 1 white2 3 6 1 $le

Precrsor 9Precrsor 9 Precrsor :Precrsor :$le anthocyanin$le anthocyanin

colorlesscolorless colorless colorless

33

en.yme 9en.yme 9

66

en.yme :en.yme :



Dplicate 0ecessi%e )pistasisDplicate 0ecessi%e )pistasis

eg5 Petal color in hare$ell flowerseg5 Petal color in hare$ell flowers

33 w 6w 6 $ ( 3$ ( 3 w 6w 6 $$

F9 3F9 3 6 6

;9 3 ;9 3 $ $$ $;9 w w 6 ;9 w w 6

9999 w w $w w $ $$

Phenotypic ratio,Phenotypic ratio,



Dominant )pistasisDominant )pistasis

)pistatic gene e(erts its affect with the)pistatic gene e(erts its affect with the

presence of a dominant allele5presence of a dominant allele5

eg5 /rit color in smmer s*asheg5 /rit color in smmer s*ash

K 1 yellow2 yy 1 greenK 1 yellow2 yy 1 green

3 inhi$its either color 1 white3 inhi$its either color 1 white

w has no effect on color w has no effect on color



Dominant )pistasisDominant )pistasis

eg5 /rit color in smmer s*asheg5 /rit color in smmer s*ash

33 w K y ( 3w K y ( 3 w K yw K y

F9 3F9 3 K K

;9 3 ;9 3 yyyy

;9 w w K ;9 w w K

99 w w yy99 w w yy




Dplicate Dominant )pistasisDplicate Dominant )pistasis

eg5 /rit shape in 'hepherd’s prseeg5 /rit shape in 'hepherd’s prse

A or 6 1 heart shape A or 6 1 heart shape

aa and $$ 1 narrow shapeaa and $$ 1 narrow shape



Dplicate Dominant )pistasisDplicate Dominant )pistasis

eg5 /rit shape in 'hepherd’s prseeg5 /rit shape in 'hepherd’s prse

A or 6 1 heart aa and $$ 1 narrow A or 6 1 heart aa and $$ 1 narrow

A a 6 A a 6 $ ( A a 6$ ( A a 6 $$

F9 A6 F9 A6

;9 A$ $;9 A$ $ ;9 a;9 a a 6 a 6

99 a99 a a $ $a $ $




Interaction $etween 'e( and HeredityInteraction $etween 'e( and Heredity

'e(&inflenced'e(&inflencedcharacteristiccharacteristic Determined $y atosomal genesDetermined $y atosomal genes)(pression differs $y gender )(pression differs $y gender

Male pattern $aldnessMale pattern $aldness

Dominant in males2 recessi%e in femalesDominant in males2 recessi%e in females

<ohn Adams<ohn Adams <ohn incy Adams<ohn incy Adams



Interaction $etween 'e( and HeredityInteraction $etween 'e( and Heredity

'e(&limited'e(&limitedcharacteristiccharacteristic

Determined $y atosomal genesDetermined $y atosomal genes)(pressed only in one gender )(pressed only in one gender

Coc- feathering2 atosomal recessi%eCoc- feathering2 atosomal recessi%e

)(pressed only in males)(pressed only in males

Coc-&feathered maleCoc-&feathered male Hen&feathered femaleHen&feathered female Hen&feathered maleHen&feathered male



Interaction $etweenInteraction $etween

'e( and Heredity'e( and Heredity

Cytoplasmic InheritanceCytoplasmic Inheritance

Genes fond on chromosomesGenes fond on chromosomesof cytoplasmic organellesof cytoplasmic organelles

Inherited from the maternalInherited from the maternalparent de to contri$tion ofparent de to contri$tion ofcytoplasm in o%mcytoplasm in o%m

Leaf %ariegationLeaf %ariegation

cased $y inheritancecased $y inheritance

of %aria$le chloroplastof %aria$le chloroplast

genotypesgenotypes



Interaction $etweenInteraction $etween

'e( and Heredity'e( and Heredity

Genetic Maternal )ffectGenetic Maternal )ffect

Phenotype of offspringPhenotype of offspringdepends on genotype ofdepends on genotype ofthe maternal parentthe maternal parent

Direction of snail shellDirection of snail shell

coiling is determinedcoiling is determined$y genotype of female$y genotype of female

parentparent



Interaction 6etween 'e( and HeredityInteraction 6etween 'e( and Heredity

GenomicGenomicImprintingImprinting

)(pression of atosomal genes)(pression of atosomal genesdiffers depending on whether theydiffers depending on whether theyare inherited from the male orare inherited from the male orfemale parentfemale parent

Prader&3illi 'yndromePrader&3illi 'yndrome

Deletion on chromosome 9@Deletion on chromosome 9@

inherited from fatherinherited from father

Angelman 'yndrome Angelman 'yndrome

Deletion on chromosome 9@Deletion on chromosome 9@

inherited from motherinherited from mother



Anticipation Anticipation

Trait is more strongly e(pressed orTrait is more strongly e(pressed or

e(pressed earlier in scceeding generationse(pressed earlier in scceeding generations

HntingtonHntingtonDiseaseDisease

Increase in nm$er of trincleotideIncrease in nm$er of trincleotiderepeats in gene for protein Hntingtinrepeats in gene for protein Hntingtinleads to lethal nerodegenerati%eleads to lethal nerodegenerati%edisorder with personality changes anddisorder with personality changes and

ncontrolla$le mo%ements5ncontrolla$le mo%ements5

+m$er of repeats e(pands with+m$er of repeats e(pands withscceeding generations5 Disease occrsscceeding generations5 Disease occrsearlier and is more se%ere5earlier and is more se%ere5



Allen"B29;#

age @?

Linda"2::#

Nristen

"B2::#

age B?

Ann

"B2::#

age ;F

Andrew

"F2#

age ;

De$$ie

"9;2#

Greg

"9929F#

+athaniel

":29F#

age ;@

6ill

"29:#

Pala

"9;29:#

)%an

"not tested#

Christina

"F;2#

age :

<oseph

"2#

<ama

"29#

)(pansion of the Trincleotide 0epeat for Hntington’s Disease



)n%ironmental )ffects)n%ironmental )ffects

Phenotype is dependent pon the presencePhenotype is dependent pon the presence

of a specific en%ironment5of a specific en%ironment5

The temperatre&sensiti%e prodct of the himalayan alleleThe temperatre&sensiti%e prodct of the himalayan allele

is inacti%ated at high temperatres5is inacti%ated at high temperatres5



Penetrance and )(pressi%ityPenetrance and )(pressi%ity4 Penetrance 1 percentage of indi%idals with aPenetrance 1 percentage of indi%idals with a

gi%en genotype who e(hi$it the phenotypegi%en genotype who e(hi$it the phenotype4 )(pressi%ity 1 e(tent to which genotype is)(pressi%ity 1 e(tent to which genotype is

e(pressed at the phenotypic le%el "may $e de toe(pressed at the phenotypic le%el "may $e de to

allelic %ariation or en%ironmental factors#allelic %ariation or en%ironmental factors#

Gene Interaction NS W12

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