Genetic Terms and Notation
 
 
DEFINITION
EXAMPLE
CHROMOSOME
Microscopic body that carries the GENES for color and other traits. One chromosome can carry hundreds of genes. Males have two X chromosomes, females have an X and a Y.
DOMINANT
A trait which rules over others. The normal type is dominant to almost all mutations.
GENE
An element in a CHROMOSOME by which hereditary traits are determined. Lutino is a gene carried by the X chromosome.
GENOTYPE
Genetic makeup. A Male XC X would have a Genotype of Normal split to Cinnamon.
MUTATION
Any variance from the normal that can replicate itself. Pearl-Pied is a double mutation.
PHENOTYPE
The appearance of a bird. A Male XC X would have the phenotype of Normal.
RECESSIVE
Submissive to the DOMINANT or normal; unlike a SEX LINKED GENE, which is carried by the X CHROMOSOME The Pied gene is recessive to normal.
SEX LINKED
Carried on the X or male CHROMOSOME Pearl is a Sex Linked mutation.
SPLIT
Having a GENOTYPE where a genetic trait is hidden by DOMINANT normal. NOTE: Females can never be split to a SEX LINKED MUTATION (Cinnamon, Pearl, Yellowcheek or Lutino). A male XC XP would be split for both Cinnamon and Pearl. A female X Y pN is split to Pied.
 
 
 
Diagramming Abbreviation
Written Abbreviation
Cinnamon
C
Cin
Lutino
L
Lut
Pearl
P
Prl
Fallow
ff
Fal
Pied
pp
Pd
Recessive Silver
ss
Sil
Whiteface
ww
WF
Yellowcheek
Yc
Yck
Dominant Silver
SS
DS
Pastel Face
pa
Pas
Male Chromosome
X
(none)
Female Chromosome
Y
(none)
Split
/
/
Double Mutation
(none)
"-"
(i.e., Lutino-Pied)
 
 
 
Sire: GENTOTYPE
Dam: GENOTYPE
SONS
DAUGHTERS
 
 
 
   
pN ww
ss fN
all possible combinations
of their autosomal genes.
 

 Back to the Top


Sex-Linked Mutations

 

 
EXAMPLES OF SEX LINKED GENETIC CODES
 
 
GENOTYPE
PHENOTYPE
XL X Male Normal/Lutino Normal Grey
XC XP Male Normal/Cinnamon AND Pearl Normal Grey
X XCP Male Normal/Cinnamon-Pearl Normal Grey
XL XLP Male Lutino split to Pearl Lutino
XCP Y Female Cinnamon-Pearl Cinnamon-Pearl
XL Y Female Lutino Lutino
XYc Y Female Yellow-Cheek Yellow-Cheek
 

 Back to the Top


Simple Recessive Mutations

 

 
GENETIC CODE DESCRIPTION
pp Pied
pN Split to Pied
Np Split to Pied
 

Note: It doesn't matter whether the mutated gene is coded first or last in the pair, as both will show split.

 Back to the Top


Calculating Sex-Linked Genetic Codes
 
 
MALE: X1 X2  FEMALE: X3 Y
   
MALE:  X1 X2 FEMALE:  X3 Y 
F
 
X1  X3
 

 

   
MALE: X1 X2 FEMALE: X3 Y
O X1 X3   
X1 Y 
 

 

 
MALE: X1 X2 FEMALE: X3 Y
 
X1 X3
  
X1 Y 
I   
X2 X3
 
 
   
  MALE: X1 X2 FEMALE: X3 Y 
  
X1 X3
  
X1 Y 
L   
X2 X3 
  
X2 Y 
 
   
Male: XC XL
Female: XP Y
   
   
 
   
Male: XC XL
Female: XP Y
XC XP
 
   
 
 
 
Male: XC XL
Female: XP Y
XC XP
 XC Y
   
 
   
Male: XC XL
Female: XP Y
 
XC XP
 
XC Y
 
XL XP
 
 
   
Male: XC XL
Female: XP Y
 
XC XP
 
XC Y
 
XL XP
 
XL Y
 
  · 25% will be Normal Grey males split to Cinnamon and Pearl

· 25% will be Normal Grey males split to Lutino and Pearl

· 25% will be Cinnamon females, and

· 25% will be Lutino females.

This is what we call a Sex Linked nest .... you can determine the sex of the babies by the colors produced simply because you know a little bit now about genetics. All your males will have the Phenotype or appearance of being Normal, while your females will be either Cinnamon or Lutino.

 Back to the Top

 


Adding Autosomal Recessives
 
 
NN pp
Np
Np
Np
Np

 

 
pN pN
 
   
MALE: XC XL
FEMALE: XP Y 
XC XP
XC Y
XL XP
XL Y
 
   
pN pN
pp
pN
Np
NN
   
MALE: XC XL pN
FEMALE: XP Y pN
XC XP pp
XC Y pp
XC XP pN
XC Y pN
XC XP Np
XC Y Np
XC XP NN
XC Y NN
XL XP pp
XL Y pp
XL XP pN
XL Y pN
XL XP Np
XL Y Np
XL XP NN
XL Y NN
 
SONS
  · 12.5% would be Pied split to Cinnamon and Pearl;

·  25% would be Normal split to Cinnamon, Pearl, and Pied;

· 12.5% would be Normal split to Cinnamon and Pearl;

· 12.5% would be Pied split to Lutino and Pearl;

·  25% would be Normal split to Lutino, Pearl, and Pied; and

· 12.5% would be Normal split to Lutino and Pearl.

 
DAUGHTERS
 
· 12.5% would be Cinnamon-Pied;

· 25% would be Cinnamon split to pied;

· 12.5% would be Cinnamon;

· 12.5% would be Lutino-Pied;

· 25% would be Lutino split to pied; and

· 12.5% would be Lutino.

 
Calculating Percentages

 

  •  Figure the number of combinations for EACH recessive pairing. In this case there is only ONE possible combination of the recessive genes: fN. There are THREE possible combinations of whiteface: ww, wN, and NN (which we leave blank). There are also THREE possible combinations of pied: pp, pN, and NN.
  • Calculate the number of combinations by multiplying the number of possibilities:
  • 4 sex-linked
    x 1 fallow
       4
    x 3 whiteface
    12
    x 3 pied
    36 possible combinations
       
    pN pN
    pp
    pN
    Np
    NN
       
    pN sN pN sN
    pp ss - visual pied and silver
    pp sN - visual pied split to silver
    pp Ns - visual pied split to silver
    pp NN - visual pied (not carrying silver)
    pN ss - visual silver split to pied
    pN Ns - split to silver and pied
    pN NN - split to pied (not carrying silver)
    Np ss - visual silver split to pied
    Np sN - split to silver and pied
    Np Ns - split to silver and pied
    Np NN - split to pied (not carrying silver)
    NN ss - visual silver (not carrying pied)
    NN sN - split to silver (not carrying pied)
    NN Ns - split to silver (not carrying pied)
    NN NN - not carrying pied or silver
     There are 16 different ways the pairs of genes could combine.
     
       
    MALE: XP XP pN sN FEMALE: X Y pN sN 
     
       
    SONS
    DAUGHTERS
    6.25% Silver-Pied/Pearl 6.25% Silver-Pearl-Pied
    12.50% Pied/Pearl & Silver 12.50% Pearl-Pied/Silver
    6.25% Pied/Pearl 6.25% Pearl-Pied
    12.50% Silver/Pearl & Pied 12.50% Silver-Pearl/Pied
    25.00% Normal/Silver,Pearl & Pied 25.00% Pearl/Silver & Pied
    12.50% Normal/Pearl & Pied 12.50% Pearl/Pied
    6.25% Silver/Pearl 6.25% Silver-Pearl
    12.50% Normal/Silver & Pearl 12.50% Pearl/Silver
    6.25% Normal/Pearl 6.25% Pearl
         
    MALE: XP XC pN sN
    FEMALE: X Y pN sN
    SONS: XP X pp ss DAUGHTERS XP Y pp ss
      XP X pp sN   XP Y pp sN
      XP X pp NN   XP Y pp NN
      XP X pN ss   XP Y pN ss
      XP X pN sN   XP Y pN sN
      XP X pN NN   XP Y pN NN
      XP X NN ss   XP Y NN ss
      XP X NN sN   XP Y NN sN
      XP X NN NN   XP Y NN NN
      XC X pp ss   XC Y pp ss 
      XC X pp sN   XC Y pp sN
      XC X pp NN   XC Y pp NN
      XC X pN ss   XC Y pN ss
      XC X pN sN   XC Y pN sN
      XC X pN NN   XC Y pN NN
      XC X NN ss   XC Y NN ss
      XC X NN sN   XC Y NN sN
      XC X NN NN   XC Y NN NN
     
    WHEW!
       
    SONS
    DAUGHTERS
    3.125% Silver-Pied/Pearl 3.125% Silver-Pearl-Pied
    6.25% Pied/Pearl & Silver 6.25% Pearl-Pied/Silver
    3.125% Pied/Pearl 3.125% Pearl-Pied
    6.25% Silver/Pearl & Pied 6.25% Silver-Pearl/Pied
    12.50% Normal/Silver,Pearl & Pied 12.50% Pearl/Silver & Pied
    6.25% Normal/Pearl & Pied  6.25% Pearl/Pied
    3.125% Silver/Pearl 3.125% Silver-Pearl
    6.25% Normal/Silver & Pearl 6.25% Pearl/Silver
    3.125% Normal/Pearl 3.125% Pearl
    3.125% Silver-Pied/Cinnamon 3.125% Silver-Cinnamon-Pied
    6.25% Pied/Cinnamon & Silver 6.25% Cinnamon-Pied/Silver
    3.125% Pied/Cinnamon 3.125% Cinnamon-Pied
    6.25% Silver/Cinnamon & Pied 6.25% Silver-Cinnamon/Pied
    12.50% Normal/Silver,Cinnamon & Pied 12.50% Cinnamon/Silver & Pied
    6.25% Normal/Cinnamon & Pied 6.25% Cinnamon/Pied
    3.125% Silver/Cinnamon 3.125% Silver-Cinnamon
    6.25% Normal/Silver & Cinnamon 6.25% Cinnamon/Silver
    3.125% Normal/Cinnamon 3.125% Cinnamon
     
     

     Back to the Top


     
    Genetic Crossover
      2. It is not necessary for the entire clutch to be affected by crossover. Only one bird out of a clutch, for example, could have sex-linked genes that result from a crossover. 3. Crossover occurs, on the average with Cinnamon, Pearl and Lutino, only 25-30% of the time. (Yellowcheek has a much lower percentage of crossover.)  Let's look at crossover a little closer, using a normal male split to cinnamon and pearl, mated to a normal female.  
    MALE: XP XC FEMALE: X Y
    XP X
    XP Y
    XC X
    XC Y
     
     
     X P   X C = X   XCP
     
    MALE: X  XCP FEMALE: X  Y
    X X
    X Y
    XCP X
    XCP Y
     
    X C P   X  =  XC  XP

     

     Back to the Top

     


     
    Dominant Silver

     

     
    Male: X X SS Female: X Y (NN)
    Sons: X X SN Daughters: X Y SN
     
     
     
     
    DOMINANT SILVER 
    RECESSIVE SILVER 
    SS NN
    SN 
     
     
    SN NN
    SN 
    NN 

      

    SN SN
    SS (25%) 
    SN (50%) 
    NN (25%) 
     
     
    SS SN
    SS 
    SN 
     
    SS SS
    SS 
    ss NN
    sN 

      

    sN NN
    sN 
    NN 

      

    sN sN
    ss (25%) 
    sN (50%) 
    NN (25%) 

      

    ss sN
    ss 
    sN 
      
    ss ss
    ss 
     
     
       
    Male: XP XP  Female: X Y
    Sons: XP X  Daughters: XP Y
     
       
    Male: Single Factor (SN) Female: Double Factor (SS)
    Double Factor (SS) (50%)
    Single Factor (SN) (50%)

     
     

     
    Male: XP XP SN Female: X Y SS
    XP X SS
    XP Y SS
    XP X SN
    XP Y SN
     
     
     
     

     

    Male: Whiteface (ww) Female: split whiteface (wN)
    ww (50% whiteface)
    wN (50% split whiteface)
     
       
    Male: XP XP SN ww Female: X Y SS wN
    XP X SS ww
    XP Y SS ww
    XP X SN ww
    XP Y SN ww
    XP X SS wN
    XP Y SS wN
    XP X SN wN
    XP Y SN wN
     
     
     

     Back to the Top

     


     
    Producing an Albino Cockatiel

     Now, let me start by saying THERE IS CURRENTLY NO SUCH THING AS A TRUE ALBINO COCKATIEL! Oh, I can hear the phone ringing now...."What do you mean thereís no such thing as an albino cockatiel? Iíve been breeding them for years!" Before you start dialing, read on: what we call an albino cockatiel certainly does have the PHENOTYPE (appearance) of an albino. It has all white feathers, pink feet, red eyes, and no cheek patch. Sounds like an albino to me! But the reason it APPEARS to be an albino is that it is really a combination of the sex-linked mutation, Lutino, which "hides" the melanin pigment (gray, cinnamon, silver, etc.), and the autosomal recessive mutation, whiteface, which "hides" the lipochrome (yellow and orange) pigments. Thus, a bird is created without pigmentation, and appears to be albino. GENETICALLY, however, it is NOT AN ALBINO....it is a Lutino-Whiteface. It is a COMBINATION OF TWO MUTATIONS, not its own true mutation. The so-called "albino" cannot pass along ONE GENE to produce another albino. Instead, one sex-linked gene and one recessive gene are passed to the offspring. If a Lutino-Whiteface (albino) male were mated to a normal hen, the genetic chart would look like this:

     

    Male: XL XL ww  Female:   X Y 
    Sons: XL X wN Daughters: XL Y wN
     
       
    Male: XL XL Female: X Y ww
    Sons: XL X wN Daughters: XL Y wN
     
       
    Male: XL X wN Female: X Y ww
    XL X wN
    XL Y wN
    XL X ww
    XL Y ww
    X X wN
    X Y wN
    X X ww
    X Y ww
     
     

     
    Pastel Face
     
       
    Male: X X papa Female: X Y 
    Sons: X X paN Daughters: X Y paN
     
     

     

    Male: XP XP papa pp Female: X Y pp
    Sons: XP X paN pp Daughters: XP Y paN pp
     
     
     
    Normal / Pastel x Normal
    paN NN
    paN (50%)
    NN (50%)
    Normal / Pastel x Normal/Pastel
    paN paN
    papa (25%)
    paN (50%)
    NN (25%)
    Pastel x Normal
    papa NN
    paN (100%)

     

    Pastel x Normal/Pastel
    papa paN
    papa (50%) 
    paN (50%)

     

    Pastel x Pastel
    papa papa
    papa (100%)

     

    Normal/Pastel x Normal/Whiteface
    paN wN
    paw (25%)-Pastel split Whiteface 
    paN (25%)-split Pastel
     
    wN (25%)-split Whiteface
     
    NN (25%)-not split

     

    Normal/Pastel x Whiteface
    paN ww
    paw (50%)-Pastel split Whiteface 
    wN (50%)-split Whiteface

     

    Pastel/Whiteface x Normal
    paw NN
    paN (50%) 
    wN (50%)

     

    Pastel/Whiteface x Normal/Whiteface
    paw wN
    paw (25%)
    paN (25%)
     
    ww (25%)
    wN (25%)
    Pastel/Whiteface x Whiteface
    paw ww
    paw (50%) 
    ww (50%)

     

    Pastel/Whiteface x Pastel
    paw papa
    papa (50%) 
    paw (50%)

     

    Pastel/Whiteface x Pastel/Whiteface
    paw paw
    papa (25%) 
    paw (50%)
     
    ww (25%)

     

         

     

     Back to the Top

      
      

    About the Author
     

    Cynthia Kiesewetter has been owned by cockatiels, as of this writing, for approximately 15 years. It was her father, James Dodson (one of the founders of the Connecticut Budgerigar Society), who instigated her interest in aviculture. His knowledge of budgerigar genetics was instrumental in spurring her to learn more about cockatiel genetics.

     
    Cynthia was active in her local club, Connecticut Association for Aviculture, for 8 years as Secretary, Bulletin Editor, Show Advisory Committee Chairperson, and Membership Co-chairperson with her husband, Michael. They have also been members of the American Federation of Aviculture, Society of Parrot Breeders and Exhibitors, American Cockatiel Society, National Cockatiel Society, and the North American Cockatiel Society.

     
    In the National Cockatiel Society, Cynthia (better known as Cindy to her friends)  served as Connecticut State Coordinator, Nomination Chairperson, and, from early 1993 to late 1997, Band and Membership Secretary and NCS Magazine Genetics Consultant. She was awarded the N.C.S. Presidential Award in 1993, 1994. 1995, and 1996 for outstanding contributions.  Cynthia and Michael also created and maintained an Internet site for the National Cockatiel Society for two years.  Cynthia resigned her NCS duties in late 1997 to form the North American Cockatiel Society and dedicate herself more to her birds and her newly expanding family.   

    Copyright 2000 by Cynthia Kiesewetter and the North American Cockatiel Society.

     

    All rights reserved. No part of this publication may be used or reproduced in any form or by any means, or stored in a database or retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the author. Opinions expressed here do not necessarily reflect the opinions of NACS, its membership, or officers.