Why do Huskies have blue eyes?

Humans have been exercising selection in dogs since the domestication of the wolf. In the first instance we found a natural and quite gradual selection in the way in which the first dogs were domesticated; in second, an intense artificial selection during the formation of the most modern races.



An unintended consequence of this selection is that the canine genome now encodes a phenotypic diversity - characteristics that a gene, eg, blue eyes or brown eyes - can express dramatically high. This variety is susceptible to genetic analysis, and this is demonstrated by the latest study published recently in the journal PLOS Genetics by Adam Boyko and Aaron Sams, of the company Embark Veterinary Inc, and conducted in collaboration with the University of Veterinary Medicine of Cornell.

According to the authors, this represents the first consumer genomics study conducted in a non-human model and the largest study of the canine genome to date. It addresses the reason why huskies have blue eyes. In dogs, the blue eyes are iconic of the Siberian husky, a race of northern latitudes and although it is known that two genetic variants underlie the color of blue eyes in some dogs, these do not serve to explain the trait of the huskies.

To find out this last reason, Boyko and Sams who in his company had the sequenced genome of 6,070 dogs, made use of the information provided by the owners of the dogs and who, through online surveys and photographs, provided the scientists with data on the phenotype studied, in this case the eye color.

Thus, scientists discovered that chromosome 18 near the ALX4 gene, which plays an important role in mammalian eye development, was strongly associated with the variation in blue color for the eyes, mainly in Siberian huskies, but also in the Australian shepherds that do not show the merle mutation (which dilutes the color of melanin in dogs and mice). Thus, only one copy of the variant is sufficient to cause blue eyes or heterochromia - blue and brown eyes - in many of the individuals studied.

However, some dogs with the variant did not have blue eyes, so the researchers hypothesize that other genetic or environmental factors could be involved in the expression of this phenotype. Future studies on this mechanism may lead to the discovery of a new way in which blue eyes develop in mammals.



On the other hand, from a broader perspective, the results emphasize the power of knowledge based on the data provided by consumers. In words that Aaron J. Sams sends us via press release: "by using the genetic data of our clients' pets, combined with the colors of the eyes reported by them, we have discovered a genetic duplication that is strongly associated with the color of blue eyes In a single year, we gathered enough data to make the largest canine study of its kind, "he adds. "In addition, we are currently conducting similar research projects with respect to morphological or health-related characteristics, which benefit reproduction efforts and the welfare of dogs in the first place, but are valuable in the same way for studies. in humans, since dogs and humans exhibit many physical features, behaviors and analogous diseases in a shared environment, with this new methodology we hope to achieve great advances in the field of genetics and medicine ", concludes the researcher.

Rainforest animals

What animals live in the rainforest?

The tropical forests have an enormous biodiversity. It is estimated that up to half of the species that inhabit the planet, are living in this ecosystem. We can find jungles of this type in the vicinity of Ecuador, South America, Africa, some Southeast Asian Islands, Mexico, Central America, Madagascar, Indochina or Northwest Australia and in them we can find fascinating and very varied animals. In this article we talk about which animals live in the rainforest.



What conditions do tropical forests have?

The conditions that occur in the rainforests are characteristic of the low latitudes in which they are found, with an average temperature of around 25ºC to 30ºC throughout the year and rainfall that can occur throughout the year, including daily , it is common to reach a minimum volume of 100 mm up to about 400 inches of rainfall per year, although this is quite variable. What is common is that these forests reach a very high humidity, from 75 to 90%. These forests, unlike others, do not change their conditions much over a year, but are more or less stable. Given this great humidity and heat, large clusters of clouds are created over these forests.

Due to this high degree of humidity, they are also very dense in terms of vegetation, being common a broadleaf vegetation: trees, shrubs, ferns, etc. That prevent sunlight from reaching the ground, so it also favors the development of mosses and fungi.

Strata of the rainforest

These forests are usually divided into 4 zones or strata (from top to bottom) and they inhabit different animals, because in each stratum there are somewhat different conditions.

  • Emerging stratum: it is the area determined by the tallest trees, which are usually hardwood and broadleaf, reaching up to 60 meters in height. In this area, the strong wind blows and pulls the seeds, which are deposited in the surrounding land for the new generation. It is an area inhabited by bats, butterflies, monkeys and birds.
  • Stratum of the canopy: it is considered the primary layer of the forest. It is formed by a labyrinth of branches and leaves that protect the lower strata of sunlight and rain. In this area food abounds and you can find butterflies, frogs, toucans and snakes.
  • Underbrush layer: also protects the lower layer of sunlight. In this stratum, shrubs of up to 4 meters live and most insects, tree frogs, snakes, jaguars and leopards inhabit it.
  • Stratum of the soil: it is a very dark zone, where vegetation hardly develops. This land cover, buds, branches and twigs. In this area, so-called soil recyclers live, such as giant anteaters, cockroaches and large millipedes. It is called recyclers because they are animals that feed and decompose leaves or plants.



Main animals that live in the tropical jungle

In these forests live so many animals that have not yet documented all the species that inhabit them. Some examples of animals that live in the jungle, both carnivores and herbivores, are:

  • Jaguars: are common in the jungles of America, is the largest predator of the jungle with other cats and crocodiles. It is a feline with golden and yellow fur with some small reddish to black spots. They can reach 130 kg in weight and 2.30 meters. It is an opportunistic carnivore that feeds on mammals, reptiles, insects, fish and invertebrates.
  • Pumas: feline up to two meters and 72 kg in weight. It feeds on insects and large ungulates.
  • Ocelot: feline of fur with spots and average size that measures up to 90 centimeters and weighs 11 kg. It feeds on rodents, monkeys or reptiles. It is one of the animals in danger of extinction in Mexico.
  • Tiger: the largest feline there is. The tiger is a very fast animal that can reach 300 kg of weight and 380 centimeters.
  • Crocodile of the Nile: it is a reptile that lives in jungles of Africa. It feeds on mammals, fish or other reptiles. Above all, he captures them when they come to drink.
  • Elephant: are relatively medium elephants for their species, up to two and a half meters. There is an African elephant and Asian elephants, like the elephant of Sumatra, who live in the jungle. The rest of the elephants that are larger live in areas like the African savanna and not in jungles.
  • Capybaras: are the largest rodents. They live in herds and are of twilight activity
  • Cockatoos: there are up to 21 species of cockatoos in the jungle. They are very showy birds.
Other animals in the rainforest are leopards, panthers, lemurs, anteaters, rock pythons, mambas, tapirs, eagles, macaws and numerous species of parrots, ostriches, chimpanzees and other monkeys.