Hybrid (biology)

Hybrid (biology)

In biology and specifically, genetics, the term hybrid has several meanings, all referring to the offspring of sexual reproduction.

1. In general usage, hybrid is synonymous with heterozygous: any offspring resulting from the mating of two genetically distinct individuals
2. a genetic hybrid carries two different alleles of the same gene
3. a structural hybrid results from the fusion of gametes that have differing structure in at least one chromosome, as a result of structural abnormalities
4. a numerical hybrid results from the fusion of gametes having different haploid numbers of chromosomes
5. a permanent hybrid is a situation where only the heterozygous genotype occurs, because all homozygous combinations are lethal.

From a taxonomic perspective, hybrid refers to:

1. Offspring resulting from the interbreeding between two animals or plants of different species. See also hybrid speciation.
2. Hybrids between different subspecies within a species (such as between the Bengal tiger and Siberian tiger) are known as intra-specific hybrids. Hybrids between different species within the same genus (such as between lions and tigers) are sometimes known as interspecific hybrids or crosses. Hybrids between different genera (such as between sheep and goats) are known as intergeneric hybrids. Extremely rare interfamilial hybrids have been known to occur (such as the guineafowl hybrids). No interordinal (between different orders) animal hybrids are known.
3. The third type of hybrid consists of crosses between populations, breeds or cultivars within a single species. This meaning is often used in plant and animal breeding, where hybrids are commonly produced and selected because they have desirable characteristics not found or inconsistently present in the parent individuals or populations. This flow of genetic material between populations or races is often called hybridization.