Jeffrey Low

Thursday, July 31, 2014

The long tail and leucistic traits in combination

This is DDS278, my two months old female white-rumped shama, a gift from my friend David and very much treasured by me. She is one of the offsprings resulting from a pairing of a normal coloured long-tailed male and a leucistic short-tailed female. In my opinion, she is a beautiful female with an overall good structure. I am especially attracted to her flat looking top skull with the distinct drop, down the back of the neck.

She is short-tailed with the normal colours of her species but that is only her phenotype. However, it is her genotype that is important to provide the foundation for producing long-tailed leucistic birds in the future. She is heterozygous for the long tail trait and heterozygous as well for the leucistic trait.


I have done some calculations using the punnett square and I think the result may be of some use to formulate a breeding strategy towards the goal of producing long-tailed leucistic shamas.

If DDS278 is to be paired up with a male shama that is also heterozygous for both these traits (a dihybrid cross), the probability of getting long-tailed leucistic offsprings is 1 out of 16. The same pairing will also have the probabilities of yielding 3 long-tailed but normal coloured offsprings out of 16, 3 short-tailed leucistic offsprings out of 16 and 9 short-tailed normal coloured offsprings out of 16.

From the punnett square, the long-tailed, normal coloured offsprings are 66% hets for leucistic and the short tailed leucistic offsprings are 66% hets for long tail. In other words, every long-tailed, normal coloured offspring from such dihybrid pairings has a  66% chance of also being heterozygous for the leucistic trait and every short-tailed leucistic offspring from the same pairing has a 66% chance of also being heterozygous for the long tail trait.

Also from the punnett square, out of the 9 short-tailed normal offsprings, the probabilities are 4 being  heterozygous for both long tail and leucistic, 2 being heterozygous only for long tail, 2 being heterozygous only for leucistic and 1 being normal short tail without the genotype for both these traits.