Interesting genetic facts

  • Two individuals share as much as 99.9% of the same genetic material and differ in only 0.1% of it.
  • Genetic similarity. People share 7% of genetic material with the E.coli bacteria, 21% with worms, 90% with mice and 98% with chimpanzees.

Genetic comparison

  • If you were to recite the entire ATCG sequence, pronouncing each of its 3 billion letters the genetic material notation is made of at a rate of 100 ATCG sequences per minute without sleeping, eating or drinking, you would cite for 57 years.
  • If all 46 chromosomes were combined and arranged lengthwise, the total length would be 1.8 meters. If all the chromosomes from all the nuclei in the human body (1014 cells) were to be arranged lengthwise, it would measure around 180 000 million kilometres. For a better understanding, compare it to the distance from the Earth to the Sun which measures 150 million kilometres. The length of the DNA would thus be one thousand times greater.
  • The full stop at the end of a sentence is the size of one thousand cell nuclei.
  • African ethnic group Yoruba has an unusually high birth rate of twins, making it an interesting study group for research in the field of heritability.
  • There is genetic proof indicating that the Sans are one of oldest peoples in the world. They may well be the most ancient, and are considered to be a “genetic Adam”.
  • The banana is a fruit which originated in Asia. During the period of one of the largest human migrations (between 1000 B.C. and 300 A.C.), it was brought to Africa.
  • In the case of autosomal recessive hereditary diseases, the recessive gene, situated on an autosomal chromosome, is passed on in the family. If a person has only one copy of this gene, he is its carrier without being aware of it, as the disease has not developed.
  • The haemophilia is recessive disease and linked to the sex chromosome X. Women have two X chromosomes. That is why only individuals carrying two recessive genes develop the disease. The women who carry only one recessive gene are the transmitters of the disease. All men with the recessive gene will develop the disease as they only have one X chromosome. These facts were well known with the Jewish population, as the sons of the women who were considered to be transmitters of the disease were exempt from circumcision.
  • Beside the DNA present in the nucleus, people also have DNA present in mitochondria. This DNA is only inherited from the mother and it is used in studies related to female ancestry. An interesting fact noticed in bees is that their mitochondrial DNA can also be inherited from the father.

Heritability

  • There are genetic abnormalities that occur in mitochondrial DNA and they also affect an individual. Mitochondrial DNA is inherited from the mother, for at the time of fertilization of an egg the mitochondrion of the sperm does not enter the egg. The egg contains mother's mitochondria and as such the child only possesses mother's mitochondria. Due to such mode of inheritance, the genetic abnormality will be expressed in all children of the abnormality-carrying mother and in no children of the father with the same abnormality.
  • On average, one out of 180 children is born with a chromosomal abnormality. The result of the most frequent abnormality is Down's syndrome.
  • The Italian regions of Toscana and Umbria are special. The people there are genetically different from the other Italian regions because of Etruscan genetic heritage in this area.
  • According to some linguistic theory, the Basques originally hail from Russia, for their haplotype is the same as the haplotype found in inhabitants of some regions of Russia.
  • Genetic studies form a theory of three migrations of the Hans from the North to the South of China.
  • Only 2 percent of the human genome contains information regarding the formation of proteins. All the rest are so called non-coding regions.
  • In a typical group of 50 African monkeys, there are more genetic variations than in the entire human race. This means that the entire human race is the descendant of a small group of people from prehistoric times. This scientific phenomenon is also referred to as a »bottleneck«. The phenomenon is probably the consequence/result of unfavourable weather conditions which lead to the death of most of the prehistoric people. The entire human race developed from a small group of survivors.
  • The modern Maltese people genetically correspond to certain Lebanese, fact that supports the theory that most Maltese people are the descendants of the ancient Phoenicians.

 

Species Human being Hen Drosophila melanogaster (wine fly) Butterfly Corn Rice
Number of chromosomes 46 78 8 around 380 20 24
Number of genes (approx.) 25 000 23 000 14 000 unknown 59 000 50 000
Length of genome (million base pairs) 3 300 1000 165 124 900 2 500 441