Scientists discover “mixed” lizards in Puerto Rico

In school, you learn about natural selection and how, over millions of years, genetic, geographic, and environmental factors Environment They may favor the creation of new species that are better adapted to their environment.

However, there comes a time when the new species is no longer able to mate and reproduce. In other words, they are genetically isolated. For example, a dog and a cat cannot have “small cats”.

But there are also cases in which the new species are still similar enough to reproduce and produce hybrid (“mixed”) offspring. For example, “chickens” can be obtained by crossing a guinea and a rooster.

hodgepodge genetics Having hybrids is usually a problem. Some people die before birth or soon after birth. If they reach adulthood, most of them are not very successful and fail to reproduce.

But, from time to time, hybrid organisms get caught in the “lottery.” evolutionaryAnd different species are better adapted to their environment than their parents. One of these cases is happening right now with two lizards in Puerto Rico,

The two species that mate are herbivorous gardener lizards (anolis pulchellus) and the mountain garden lizard (Anolis Krugi, Although A Pulchellus Grasshoppers prefer to live in warm and sunny areas A Krugi Found more in the shade of wooded lands, scientists have seen both species throughout Puerto Rico, or so they believe.

A group of researchers, prominent among whom are Puerto Ricans javier rodriguez robles (University of Nevada at Las Vegas) and manuel leal (University of Missouri at Columbia), published in the professional journal in November molecular ecologyGenetic analysis of hybrids of A Pulchellus And A Krugi,

Scientists confirmed that the population of A Krugi They are distributed throughout Puerto Rico. However, although the phenotype (physical characteristics). A Pulchellus This made them think that these lizards also live in the entire island, the reality is something else.

From the point of view of genotype (genetic characteristics that are not always visible), Hybrid lizards have conquered the entire area to the west, crossing almost from an imaginary line lustful Until Yuko, These hybrids have become so well adapted to their environment that they are almost no longer found. A Pulchellus Cigars in western Puerto Rico.

On the contrary, to the east of the same line A Pulchellus Pure except for two hybrids identified in the El Verde region. Rio Grande,

Researchers also found hybrids are physically confused A Pulchellus Because they have on average only 17% genetic material A Krugi, that little bit dnaIts location, in particular, suggests two possible evolutionary advantages.

The first benefits relate, mainly, to cellular and immunological functions, metabolism and development of the feet, Hybrid allows lizards to better use the oxygen they breathe and move more quickly,

The second advantage lies in thermoregulation, that is, how the lizard reacts to changes in environmental temperature. This will allow the hybrids to seek food and mates early in the morning or at night, when temperatures are lower than in the middle of the day., More hours of activity means more opportunities to reproduce.

This research is important for three reasons. First, it shows that the genetic characteristics of an organism are not always reflected in its physical characteristics.

This finding also leads to the question, How many other events of hybridization have occurred or are occurring in lizards (or other animals) and have not been documented?

Ultimately, the success of hybrids of A Pulchellus And A Krugi A clear example of this is that natural selection This is not something that happened millions of years ago, but is a dynamic and contemporary force in the island environment.

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The author is Professor of Physics and Science Education at Morehead State University, Kentucky, and a member of Ciência Puerto Rico (www.ciencypr.org,