Definition of "atavistic"

Although the heterozygote gives it an atavistic appearance, the gene is not atavistic.

1889, “Experiment Station Record”, in U.S, Office of Experiment Stations

Thus the gene which produced atavistic digits in the vigorous heterozygous pentadactyl condition is a lethal monster in the homozygous condition.

1946, Reginald Ruggles Gates, Human genetics

Reactivation of a dormant atavistic gene could account for the abnormal costocoracoid ligament in humans.

2006, Roger E Stevenson, Judith G Hall, Human malformations and related anomalies

They made me feel that I was alive in the nineteenth century, a sort of atavistic remnant, a romantic shred […]

1934, Henry Miller, Tropic of Cancer, Grove Press, published 1961

The true perversion took place only in the privacy of her mind — the way she imagined an atavistic macho atop her when engaged in a mandatory contribution to the fetus-banks with some cretinous inept breeder…

1979, Norman Spinrad, A world between

Because I am atavistic enough to believe that drawing is the basic language of the illustrator, even as words comprise the basic language of the writer…

2000, Steven Heller, Marshall Arisman, The education of an illustrator