What is meant by horizontal transfer in genetics?

Horizontal transfer in genetics refers to the transfer of genetic material between different species, which occurs independently of sexual reproduction. This process is significant because it allows for genetic diversity and the rapid adaptation of organisms, especially in microbial communities. Through horizontal gene transfer, one organism can acquire genes from another, leading to new traits that can enhance survival, such as antibiotic resistance in bacteria.

This phenomenon contrasts with the more traditional vertical transfer, where genetic information is passed from parents to their offspring, as reflected in the first choice. The modification of DNA within a single species, mentioned in the third choice, does not encompass the interspecies aspect of horizontal transfer. Sexual reproduction does involve the exchange of genetic information, but this occurs typically between members of the same species, as described in the fourth choice.

Understanding horizontal transfer highlights the complex ways in which genetic information can spread beyond direct lineage, shaping the evolutionary path of organisms.