Genome

Methylation also plays an important role in genomic imprinting, which occurs when both maternal and paternal alleles are present but only one allele is expressed while the other remains inactive.

The location and base sequence of each promoter site vary for prokaryotes (bacteria) and eukaryotes (higher organisms), but they are both recognized by RNA polymerase, which can then grab hold of the sequence and drive the production of an mRNA.

Probing those connections is also leading biologists to discover proteins that are responsible for holding the organelles together and maintaining a healthy cell. Nature (Mar 10, 2019)

This is because mitochondria are only found in the female gametes or "eggs" of sexually reproducing animals, not in the male gamete, or sperm.

These factors each exhibit a characteristic dominant, co-dominant, or recessive expression, and those that are dominant will mask the expression of those that are recessive.

In 1909, Danish botanist Wilhelm Johanssen coined the word gene for the hereditary unit found on a chromosome.

If both alleles are the same, the gene is said to be homozygous.

There are many diseases caused by mutations in mitochondrial DNA (mtDNA).

The biological information contained in a genome is encoded in its deoxyribonucleic acid (DNA) and is divided into discrete units called genes.

Gene drives work by breaking the normal rules of inheritance to ensure certain genes, often modified versions, are passed on from one generation to another at a higher rate than normal. The Guardian (Jan 23, 2019)