This document discusses experiments to determine phenotypic traits that indicate genetic purity in Red Junglefowl (RJF). Crosses were performed between pure RJF and feral Carolina Bantam chickens. Results showed that some traits like leg color were expressed in hybrids, making them unreliable indicators of purity. The absence of hens' combs was lost in first generation hybrids but returned in backcrosses, indicating it only shows extreme contamination. Molecular studies reveal RJF genomes are contaminated by chickens, even in historical specimens. This raises questions about RJF conservation status and purity of remaining wild and captive populations.

1. Will the Real Chicken
Please Stand Up?
A. Townsend Peterson
The University of Kansas

3. Rome News-Tribune, 1952

10. He passed them on to a young biologist, who in turn
ultimately gave them to a wealthy amateur poultry breeder
in Alabama. This flock still exists and has given some delayed
validation to Bump’s chicken theft.

11. I. Lehr Brisbin

14. Traits of Purity
• Eclipse plumage
• Lack of hen comb
• Slender, dark legs
• Reduced crow: “cock-a-doodle”
• Shorter tail
• Shorter spurs
• Plumage abnormalities

15. Eclipse Plumage

16. Lack of Hen Comb

17. Slender and Dark Legs, Short Spurs

18. Reduced Crow
• Cock-a-doodle
versus
• Cock-a-doodle-DOOOOO

19. Shorter Tail

20. Plumage Abnormalities

27. 1867 …
present
???

28. Two Hypotheses for Contamination
• Multiple, independent events
– Suggests that pockets of pure junglefowl might
exist in particularly remote areas
• Single event with subsequent spread
– Suggests less likely to find uncontaminated
populations
– Note that most/all of the contaminant characters
are secondary sexual characteristics
– Might promote rapid spread among junglefowl
populations

29. Domestic
Chickens
Wild junglefowl ancestor

31. Domestic
Chickens
Wild junglefowl ancestor

32. RJF Problem Summary
• Widespread genetic contamination of RJF
stocks (wild and captive) via back-gene-flow
from domestic or feral chickens
• Open question as to whether contaminant
genes were introduced at many sites, or
spread from some initial site of introduction
• Raises question of whether junglefowl across
southern Asia are junglefowl, or just chickens
dressed up as junglefowl

33. NEXT QUESTION:
WHAT DOES “PURE” MEAN?

35. The Question
Which phenotypic features are
good indicators of genetic purity
in Red Junglefowl?

36. Pure Male
Junglefowl
Carolina Bantam
Hen
50% pure
75% pure
87.5% pure
2nd Pure Male
Junglefowl
93.75% pure
Every animal vouchered by specimens (skin and tissue) in the KU Biodiversity Institute

37. Experimental Design I
• Pure Red Junglefowl
– The “Richardson Strain,” taken at Dehra Dun,
northern India, in the late 1960s
• Feral Carolina Bantam Hens
– An experimental strain developed by Brisbin
through generations of exposure to natural
selection under controlled conditions

38. Carolina Bantam Chickens
• Created via 26 independent selection events
• Start with full diversity of bantam chickens
• Allow “natural” selection in Georgia forests to
“create” a breed of bantam chickens
• Brisbin at work

39. Bantam Hens: Diversity

40. 0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Proportionofphenotypesurviving
Comb
straight
rose

41. 0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
Proportionofphenotypesurviving
Wings
black
white
grey
brown
orange

42. Carolina Bantam Chickens

44. Experimental Design II
• Experimental Cross
– Male Red Junglefowl (one only, because of small
population sizes)
– Four Carolina Bantam Hens
• Control Crosses
– Male Carolina Bantam Chicken
– Four Carolina Bantam Hens

45. Parental Generation

46. Experimental Design III
Age controlled by parallel design
Both populations raised in same environment
Measurements and photos
Vouchering of differences – specimens taken and
deposited at various ages of both populations

48. Flightiness
Bad News …
take genes out into wild populations!

49. Males
Controls
Experimentals

50. Hens
Controls
Experimentals

52. Conclusions
• Some characters putatively diagnosing pure
junglefowl are expressed in F1 hybrids, and
thus are not useful indicators (e.g., leg color
and thickness, flightiness)
• One character—the absence of a comb in
hens—is immediately lost in F1 hybrids, but
gradually comes back in successive backcross
generations, so only an indicator of extreme
contamination

53. Molecular Markers of Purity
Tree has chickens and junglefowl scattered across all major
branches, even when we constrained the junglefowl to
phenotypically clean, old (i.e., before 1920) individuals!
• First attempt … mtDNA control region in old
(1800s – early 1900s) specimens

56. Genomics: Current Status
• Rubin et al. work has been repeated and
replicated using Dehradun RJF material
• Complete genome sequence now in final
stages of preparation for Dehradun RJFs
• Source of 1000s of single-nucleotide
polymorphisms that can be used as probes of
purity
• Markers are well-distributed across the
genome, such that introgression can be
detected rigorously

57. IMPLICATIONS I: MOLECULAR
STUDIES OF DOMESTICATION

58. Molecular Studies of Chickens and Junglefowl

61. IMPLICATIONS II: CONSERVATION
STATUS OF RED JUNGLEFOWL

62. Red Junglefowl have seen
extensive genomic degradation via
hybridization with domestic
chickens. Most wild populations
are now contaminated. The degree
of purity of remaining “wild” and
captive populations is an open
question

67. town@ku.edu