Hybrid organisms produced by breeding animals or plants of different species are often sterile
because their chromosomes cannot successfully pair during prophase I. The table below lists
several common hybrids and the chromosome numbers of their parent species.
Johns
Hybrid
Male Parent
Female Parent
Hybrid Chromosome
number (2n)
Mule
Donkey
(Equus africanus asinus)
2n = 62
63
QUESTION
Horse
(Equus caballus)
2n = 64
Donkey
(Equus africanus
asinus)
2n = 62
Zedonk
Grévy's Zebra
(Equus grevyi)
2n = 46
QUESTION
Dog
Wolf-
dog
Wolf
(Canis lupus)
2n = 78
QUESTION
(Canis lupus
familiaris)
2n = 78
Rye
(Secale cereale)
2n = 14
56
Wheat
Triticale
(Triticum aestivum)
2n = 42*
hexaploid species (six full sets of chromosomes)
QUESTIO
Which hybrid is MOST likely to produce fertile offspring?
QUESTIC