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Punnet Squares

Simple Mendel Genetics
 

blue = sire

pink = doe

purple = litter outcome

Color key:

blue = sire 

pink = doe

purple = litter outcome

 Definitions:

alleles - it takes two alleles to form a certain trait. Offspring receive one allele per trait from each parent.

dominant trait - A trait that will show on the offspring if one of the parents passes it on. Dominant genes are represented by upper case letters (ex. agouti [A/A] is dominant to black [a/a]. All of the offspring from this pairing will be agouti carrying black, in other words, heterozygous agouti [A/a])

heterozygous - Having two different alleles for a single trait (ex. A/a - agouti carrying black)

homozygous - Having identicle alleles for a single trait. (ex. A/A and a/a)

recessive trait - A trait that must be passed on to the offspring by both parents in order to express itself. Recessive genes are represented by lower case letters. (ex. dwarfism is a recessive gene [dw/dw] the only way to get dwarf offspring is by breeding a dwarf to another dwarf [resulting in 100% dwarf offspring], dwarf to dwarf carrier [resulting in 50% dwarf offspring], or dwarf carrier to dwarf carrier [resulting in 25% dwarf offspring])

The following calculations are assuming that neither parent carries recessives other than the ones listed in their charts.

homozygous agouti x homozygous agouti

   A A
 A  A/A  A/A
 A  A/A  A/A

100% homozygous agouti offspring [A/A]

heterozygous agouti x homozygous agouti

   A A
 A  A/A  A/A
 a  A/a  A/a

   50% homozygous agouti offspring [A/A]

   50% heterozygous agouti offspring [A/a]

 

heterozygous agouti x heterozygous agouti

   A  a
 A  A/A  A/a
 a  A/a  a/a

25% homozygous agouti offspring [A/A]

50% heterozygous agouti offspring A/a]

25% black offspring [a/a]

 homozygous agouti x black

   a  a
 A  A/a  A/a
 A  A/a  A/a

100% heterozygous agouti offspring [A/a]

 

heterozygous agouti x black

 a  a
 A  A/a  A/a
 a  a/a  a/a

50% heterozygous agouti offspring [A/a]

50% black [a/a]

 black x black

   a  a
 a  a/a  a/a
 a  a/a  a/a

100% black offspring [a/a]

 

homozygous black x blue

   g  g
 G  G/g  G/g
 G  G/g  G/g

100% heterozygous black offspring [a/a G/g]

*blue is recessive to black, therefore black is represented by G-

 heterozygous black x heterozygous black

   G  g
 G  G/G  G/g
 g  G/g  g/g

25% homozygous black offspring [a/a]

50% heterozygous black [a/a G/g]

25% blue [a/a g/g]

*blue is recessive to black, therefore black is represented by G-

blue x blue 

   g  g
 g  g/g  g/g
 g  g/g  g/g

100% blue offspring [a/a g/g]

dwarf x standard size (does not carry dwarfism)

   Dw  Dw
 dw  Dwdw  Dwdw
 dw  Dwdw  Dwdw

100% standard size carrying dwarfism [Dwdw]

dwarf carrier x dwarf carrier

   Dw  dw
 Dw  DwDw  Dwdw
 dw  Dwdw  dwdw

25% standard size not carrying dwarfism [DwDw]

50% standard size carrying dwarfism [Dwdw]

25% dwarves [dwdw]

dwarf x dwarf

   dw  dw
 dw  dwdw  dwdw
 dw  dwdw  dwdw

100% dwarves [dwdw]

dwarf x standard size (dwarf carrier)

   Dw  dw
 dw  Dwdw  dwdw
 dw  Dwdw  dwdw

50% standard size carrying dwarfism [Dwdw]

50% dwarves [dwdw]

dumbo x standard ear (does not carry dumbo)

   Du  Du
 du  Dudu  Dudu
 du  Dudu  Dudu

100% standard eared carrying dumbo [Dudu]

dumbo carrier x dumbo carrier

   Du  du
 Du  DuDu  Dudu
 du  Dudu  dudu

25% standard eared - do not carry dumbo [DuDu]

50% standard eared carrying dumbo [Dudu]

25% dumbos [dudu]

dumbo x dumbo

   du  du
 du  dudu  dudu 
 du  dudu  dudu

100% dumbos [dudu]

dumbo x standard eared (dumbo carrier)

   Du  du
 du  Dudu  dudu
 du  Dudu  dudu

50% standard eared carrying dumbo [Dudu]

50% dumbos [dudu]

hairless x standard hair (does not carry hairless)

   Hr  Hr
 hr  Hrhr  Hrhr
 hr  Hrhr  Hrhr

100% standard hair carrying hairless

hairless carrier x hairless carrier

   Hr  hr 
 Hr  HrHr  Hrhr
 hr  Hrhr  hrhr

25% standard hair - do not carry hairless [HrHr]

50% standard hair carrying hairless [Hrhr]

25% hairless [hrhr]

hairless x hairless

   hr  hr
 hr  hrhr  hrhr
 hr  hrhr  hrhr

100% hairless [hrhr]

hairless x standard hair carrying hairless

   Hr  hr
 hr  Hrhr  hrhr
 hr  Hrhr  hrhr

50% standard hair - carrying hairless [Hrhr]

50% hairless [hrhr]

standard hair x rex hair

   Re  re
 re  Rere  rere
 re  Rere  rere

50% Rex - carrying standard hair [Rere]

rex x rex

   Re  re
 Re  ReRe  Rere
 re  Rere  rere

25% double rex [ReRe]

50% rex - carrying standard hair [Rere]

25% standard hair [rere]

Standard hair x double rex

   Re  Re
 re  Rere  Rere
 re  Rere  Rere

100% rex [Rere]

rex x double rex

   Re  Re
 Re  ReRe  ReRe
 re  Rere  Rere

50% double rex [ReRe]

50% rex [Rere]

double rex x double rex

   Re  Re
 Re  ReRe  ReRe
 Re  ReRe  ReRe

100% double rex [ReRe]

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