Difference between hybrid and purebred

Introduction

In the simplest possible terms, purebreds are the offspring that result from mating between genetically similar parents while hybrids are the offspring that are the result of mating between two genetically dissimilar parents. Thus, purebred are composed of two (or more) like components while hybrids are created using two or more similar but not like components.

When used by animal breeders, the term purebred means an animal whose ancestors are all from the same breed, for instance a Labrador or Boston Terrier. In the same context the term hybrid means a cross between two breeds.

Scientifically Speaking

Genetics are defined by Mendelian Laws of Inheritance. These state that on one chromosome there different positions, or loci, that occupy a gene. A gene expresses a trait that the organism will have. Each gene has multiple expressions, for example different coloured eyes. In the simplest form a gene can be either a dominant gene represented as ‘A’ which is always expressed. A recessive gene is one which is either partially expressed in the presence of a dominant gene or fully expressed in the presence of the same recessive gene, represented by ‘a.’ Say, ‘A’ is brown hide for a cow and ‘a’ is cream and Aa together make a tan hide. If two tan parents, with Aa genetic makeup mate, their offspring can be brown with an ‘AA’ make-up, cream with an ‘aa’ make up or tan with an ‘Aa’ make-up.

Zygosity is the degree of similarity between alleles for a trait, and ‘aa’ or ‘AA’ form homozygous whereas ‘Aa’ is known as heterozygous. Breeding is the process by which certain positive traits or characteristics are exploited in future generations or offspring by the process of mating and pairing up genes by manipulating Mendel’s laws.

The concept of species is basically organisms that share similar traits due to their genetic make-up defined by the same number of chromosomes. Chromosomes come either singularly, haploid, or in pairs like in humans, one from each parent which is diploid, or multiple which is known as polyploid. When organisms of the same species mate, they produce similar offspring to them who are alike others of their species. These are purebreds. Similarly when organisms of different species produce offspring with a different genetic makeup, these are hybrids.

Purebreds

Purebreds are the result of true breeding where specimens breed true-to type when mated like-to-like. The idea is that the purebred has fundamental characteristics that are consistent, replicable and predictable. Pure breeding is of necessity carried out from a restricted gene pool which has been a cause for concern. As the positive characteristics of any species or type are perpetuated through true breeding so are the undesirable traits which are a result of inbreeding. The limited gene pool leaves purebred products susceptible to a range of congenital health issues particularly where the emphasis is on aesthetics.

Hybrids

A hybrid organism is one with parentage of two different species. In the animal kingdom, mules (horse and donkey), ligers (tiger and lion), yakalos (yak and buffalo) and so on are familiar hybrids. There are various types of hybrids possible. The most obvious kind is offspring resulting from the interbreeding of two species. The second kind is hybrids between different subspecies which include intra-specific (between subspecies), intergeneric (between genera) and interfamilial hybrids. The third sort of hybrid is that caused by selective breeding to enhance and make consistent desirable characteristics such as heat tolerance amongst certain breeds of cattle.

Conclusion

Thus, a purebred organism is of a single kind that is it is a mix or product of a single species or thing. A hybrid is made of two or more different things. While there are advantages to perpetuating the distinctive characteristics of a single breed, there are also disadvantages the most basic of which is the perpetuation of less than positive characteristics. Hybrids take advantage of the positive characteristics of varying species or subspecies to make the offspring or product ‘better’ than any one species. Selective breeding amongst farmers, horticulturists and various professionals in the field of animal husbandry have spent countless years producing plants and animals that can better serve the purpose they are produced for, from strains of black roses to sheep which have the best or most wool. The general assumption is that a hybrid strain is likely hardier than a purebred one as it has ‘hybrid vigour.’

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