Why are white genes recessive?

Plants · Research · Agriculture · Food

Dominant hereditary factors prevail over recessive ones.

red = dominant allele,
white = recessive allele

If there is a double set of chromosomes, genes are in pairs, with one gene on each chromosome. The DNA of the corresponding genes can vary somewhat, so that the genes are present in different forms (alleles). A distinction is made between dominant (Latin dominare = rule) and recessive (Latin recedere = retreat) alleles. The property of the dominant allele prevails over that of the recessive allele. The characteristic of a recessive allele is only pronounced when two recessive alleles meet, i.e. the characteristic is homozygous (pure hereditary).

If both parents have a dominant and a recessive allele (heterozygous), three out of four offspring show the dominant trait, namely all offspring who have inherited the dominant allele (see figure). The recessive trait only prevails in one of four offspring, namely the one who has inherited two recessive alleles.

This distribution of parental alleles to their offspring was first described by Gregor Mendel and is one of the "Mendelian rules". Under natural conditions it normally works as described.

Today we know mechanisms with which one can artificially influence the division of the alleles, so that in subsequent generations a desired gene always proves to be dominant and asserts itself. This principle will Gene Drive called and is brought about with the help of the gene scissors CRISPR / Cas. But a lot of research is needed before any practical applications can be considered.

See also

GenChromosomeDNA Allele homozygotheterozygousGene DriveCRISPR / Cas