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One gene is not responsible for tongue rolling

Despite tongue rolling being probably the most commonly-used example of a genetic trait in humans, it is a myth that a single gene is responsible for the skill. Studies demonstrate that tongue rolling is influenced both by genetics and by the environment. 1)

The North African blue atlas butterfly

Humans have only 46 chromosomes. The mammal with the most chromosomes is the visceral rat. The North African blue atlas butterfly has between 448 and 452 chromosomes. It has the largest number of chromosomes of any multicellular aerobic organism. 2)

Eumelanin and pheomelanin determine the hair color in humans

The amount of eumelanin and pheomelanin determine the hair color in humans. Eumelanin is dark brown, and pheomelanin is reddish. People who have large amounts of pheomelanin have red hair. 3)

Theory of heredity

The Drosophila melanogaster is a small insect from the order of flies that lives on rotting fruit. It is an invertebrate organism. Due to its easy breeding, simple crossbreeding and rapid growth, it was used by Thomas Morgan in his research on the chromosome theory of heredity. 4)

Johann Friedrich Miescher

Johann Friedrich Miescher (1844-1895) was a Swiss researcher of cell metabolism and the discoverer of nucleic acids. In 1869, he isolated nucleic acids, which he called nuclein, from oil-soaked bandages of patients. He later discovered that they are found mainly in chromosomes. 5)

Taste and smell

Only three genes are associated with sight, two with hearing and five with taste, while 1000 are associated with smell. 6)

Earwax is not dependent on genetics

It is a myth that earwax is dependent on genetics. A single gene is not responsible for the kind of earwax one has, whether it is wet or dry and what color. The wet wax allele is also not dominant over the dry one. 7)


Batology is the science that deals with the study of blackberries. Narrow specialization in the study of this genus serves to understand the very complex variation at the genetic and morphological level of blackberries, consequently also the systematics of these plants. 8)

Genetic similarities

Humans share about 90% of their genetic material with mice and 98% with chimpanzees. Almost every cell in the human body contains a complete copy of the human genome. We receive 23 chromosomes from our mother and 23 from our father. Some diseases are inherited through genes. 9)

Sharing genetic material

Two people usually share about 99.9% of the same genetic material. That 0.1% of the material makes them different. 10)

FOXC2 mutation

A mutation in a gene aptly named FOXC2 has given Hollywood icon Elizabeth Taylor two eyelashes. The technical term for this rare condition is distichiasis, and while it may seem like a desirable problem, there can be complications. According to the American Academy of Ophthalmology, this extra set of lashes is sometimes “thin and well tolerated,” but in other cases, they should be removed to prevent damage to the eyes. 11)

10 trillion cells

Humans have about 10 trillion cells. If we were to unravel our entire DNA, it would stretch six billion miles - the equivalent of traveling from Earth to the Sun 65 times. 12)

DNA cells

Almost all cells in our body have DNA, except for red blood cells. However, all red blood cells start with DNA - they simply destroy their nucleus when it is no longer needed for maturation. 13)

Monozygotic twins

Monozygotic twins share the same genetic code. But as they grow, environmental and lifestyle factors play a key role in gene expression - meaning they can develop subtle differences while looking strikingly the same. In 2015, scientists developed a DNA test that can pick up these differences. 14)


Some women may have a genetic mutation that makes them tetrachromatic, which causes their eyes to have four different types of cone cells, allowing them to see 100 million different colors compared to the million or so colors most of us see. 15)

Length of DNA

The total length of DNA in the human body exceeds several million kilometers. If one were to develop the human genome, it would be about the same length as 70 trips from the Earth to the Sun and back. Written down in text form, it would take up 400 volumes of an encyclopedia. 16)

Small percentage

Only a small percentage of variants cause disease - most have no effect on our health or development. For example, some variants change the DNA sequence of a gene but do not change the function of the protein produced by the gene. Often gene mutations that could cause a disorder are repaired. 17)

genetics.txt · Last modified: 2022/10/28 07:57 by aga