Definition of backcross in US English:



[with object]Genetics
  • Cross (a hybrid) with one of its parents or an organism with the same genetic characteristics as one of the parents.

    ‘after five generations the backcrossed dogs were indistinguishable from purebred dalmatians’
    no object ‘they backcrossed with red-flowered parents to reinforce the effect’
    • ‘The parent cultivars were crossed to produce an initial hybrid that was then backcrossed to each parent.’
    • ‘The selected individuals are either backcrossed to the recurrent parent or randomly intercrossed to produce the next generation of the families.’
    • ‘To eliminate possible additional mutations, the mutant strains were backcrossed eight times before genetic analyses.’
    • ‘Each candidate was then backcrossed to the unmutagenized parent and tetrads were dissected to ensure that the synthetic lethal phenotype resulted from a single mutation.’
    • ‘The mutations were backcrossed and checked for allelism by genetic complementation tests.’


  • An instance or result of backcrossing.

    • ‘The genotypes of all double mutants were confirmed by backcrosses to wild type.’
    • ‘However, after several backcrosses, its heterozygotes could be distinguished from the dominant homozygotes.’
    • ‘Because of the repeated backcrosses, their nuclear genome is considered to be nearly equal to that of the paternal recurrent parent.’
    • ‘After 10 backcrosses into the NIH433a genetic background, both KN433a and KN433 were identical to each other and to NIH433a at all markers examined except those in the MAT locus.’
    • ‘Genetic backcrosses were conducted to eliminate plasmid-based mutations and to verify that a single genetic locus was responsible for the 3 - AT-resistant phenotype.’