{"id":41244,"date":"2025-12-12T07:15:00","date_gmt":"2025-12-12T15:15:00","guid":{"rendered":"https:\/\/www.lifeandnews.com\/articles\/?p=41244"},"modified":"2025-12-22T09:41:49","modified_gmt":"2025-12-22T17:41:49","slug":"songbirds-swap-colorful-plumage-genes-across-species-lines-among-their-evolutionary-neighbors","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/songbirds-swap-colorful-plumage-genes-across-species-lines-among-their-evolutionary-neighbors\/","title":{"rendered":"Songbirds swap colorful plumage genes across species lines among their evolutionary neighbors"},"content":{"rendered":"\n

David Toews<\/a>, Penn State<\/a><\/em><\/p>\n\n\n\n

People typically think about evolution as a linear process where, within a species, the classic adage of \u201csurvival of the fittest\u201d is constantly at play. New DNA mutations arise and get passed from parents to offspring. If any genetic changes prove to be beneficial, they might give those young a survival edge.<\/p>\n\n\n\n

Over the great span of time \u2013 through the slow closing of a land bridge here or the rise of a mountain range there \u2013 species eventually split. They go on evolving slowly along their own trajectories with their own unique mutations. That\u2019s the process that over the past 3.5 billion years has created the millions of branches on the evolutionary tree of life.<\/p>\n\n\n\n

However, new genome sequencing data reveals an unexpected twist to this long evolutionary story. It turns out that the boundaries between species on their own branches of this tree are a little more permeable than previously thought. Rather than waiting around for new mutations to solve a particular problem, interbreeding between different species can introduce ready-made genetic advantages.<\/p>\n\n\n\n

Unraveling the story of life, one genome at a time<\/h2>\n\n\n\n
\"man
The author with a red-faced warbler (Cardellina rubrifrons<\/em>), one of the wood warbler species included in the study. Kevin Bennett<\/figcaption><\/figure>\n\n\n\n

As an evolutionary biologist<\/a>, I\u2019ve been studying the stories written in the genomes of animals for over two decades. I focus mostly on colorful songbirds called wood warblers that hail from North, Central and South America. There are approximately 115 species in total, and they come in a dazzling array of bright colors.<\/p>\n\n\n\n

Some of these birds might be familiar to you, such as the brilliant Blackburnian warbler<\/a> (Setophaga fusca<\/em>), which lights up the tops of the pine trees in the eastern forests of the U.S. and Canada during spring and summer. Other warbler species might be less familiar, like the pink-headed warbler<\/a> (Cardellina versicolor<\/em>), which lives only in the highlands of Guatemala and southern Mexico.<\/p>\n\n\n\n

The story of these New World warblers was written within the past 10 million years or so \u2013 relatively recently in evolutionary terms. They\u2019re all, in effect, \u201cevolutionary neighbors,\u201d sitting next to each other at the tips of the crown of the tree of life. In my team\u2019s most recent work<\/a>, led by evolutionary biologist Kevin Bennett<\/a>, we gathered a massive amount of data from warbler genomes \u2013 over 2 trillion base pairs, from nearly every species of warbler \u2013 to learn more about their evolutionary history.<\/p>\n\n\n\n

We found that some species have unexpectedly leaped over evolutionary hurdles by sharing solutions to evolutionary problems. We are now learning from this kind of data that species aren\u2019t just vertical, evolutionary silos, as we once thought. Instead, there is much more horizontal \u201ccross talk\u201d among the branches of the evolutionary tree.<\/p>\n\n\n\n

These warblers now join Amazonian butterflies<\/a>, cichlid fish in Africa<\/a>, as well as our own hominid lineage<\/a>, as exemplars of this process of evolutionary sharing.<\/p>\n\n\n\n

\"a
Nestlings in a hybrid zone between golden-winged (Vermivora chrysoptera<\/em>) and blue-winged warblers (V. cyanoptera<\/em>). Hybrid chicks that grow up to \u2018backcross\u2019 with one of their parent species can introduce new genes into the mix for a population. Abigail Valine<\/figcaption><\/figure>\n\n\n\n

How does evolutionary sharing actually occur?<\/h2>\n\n\n\n

Genetic sharing among evolutionary neighbors all happens through hybrids: the offspring produced when individuals from two species mate. Famous hybrids include offspring between polar and grizzly bears \u2013 affectionately called \u201cpizzly\u201d bears<\/a> \u2013 as well as mules, the offspring of horses and donkeys.<\/p>\n\n\n\n

But unlike mules, which are sterile and cannot reproduce, in instances of natural warbler hybrids, we think these rare offspring can sometimes \u201cbackcross\u201d: They breed with one of the parental species, ultimately moving genes across species boundaries. These hybrids are the genetic conduit by which genes are shared across the branches in the evolutionary tree.<\/p>\n\n\n\n

But aren\u2019t we all taught in biology class that species can\u2019t interbreed with other species? Isn\u2019t that what helps define a species?<\/p>\n\n\n\n

In reality, biology always has its exceptions and fuzzy edges. And this is one: Species result from the very gradual process of speciation, which typically takes millions of years. The taxonomic<\/a> boxes we humans like to put around \u201cspecies\u201d don\u2019t typically capture the blurry borders around lineages early in this long process, when otherwise distinct plants and animals can still interbreed.<\/p>\n\n\n\n

Indeed, my lab has described many interspecies<\/a> and intergenus<\/a> hybrids in warblers, including at least one arising from both<\/a>. We\u2019ve also identified \u201chybrid zones<\/a>\u201d between very closely related species, where hybridization is rampant.<\/p>\n\n\n\n

And if the genes within these hybrids are beneficial in the recipient species, they\u2019ll spread \u2013 just like a new, beneficial mutation passed to an offspring. In this case, it\u2019s not just a single mutation but can be a whole new complement of mutations in multiple genes.<\/p>\n\n\n\n

\"small
Wood warblers need particular genes to help them process and deposit certain pigment molecules in what they eat to make brightly colored feathers, like in this yellow warbler. Marc Guitard\/Moment via Getty Images<\/a><\/figcaption><\/figure>\n\n\n\n

Shared genes solve \u2018evolutionary problems\u2019<\/h2>\n\n\n\n

Our most recent work in wood warblers shows that the evolutionary solutions they\u2019re sharing are related to their coloration.<\/p>\n\n\n\n

In this family of birds, we previously identified<\/a> genes related to their carotenoid-based coloration. Carotenoid pigments give birds their brilliant orange, yellow and red plumes \u2013 colors that are exemplified by the aptly named yellow warbler<\/a>. But birds, like all vertebrates<\/a>, can\u2019t synthesize carotenoid pigments on their own. They need to obtain carotenoids from their diet and then chemically process them.<\/p>\n\n\n\n

But processing carotenoids appears to be an evolutionary hurdle that not all birds have jumped and a rather difficult problem to solve. Our genome sequencing shows that these warblers have more shared carotenoid genes<\/a> than other shared genes in their genome, and it\u2019s likely that different versions of carotenoid-processing genes improve the recipients\u2019 fitness.<\/p>\n\n\n\n

One carotenoid-processing gene, called beta-carotene oxygenase 2<\/a><\/em>, or BCO2<\/em>, has been shared several times within this single family of birds. Moreover, BCO2<\/em> appears to be so popular that it shows second-order sharing: passing from one species to another, and then on to a third.<\/p>\n\n\n\n

A sign of quality on the mating circuit<\/h2>\n\n\n\n

My colleagues and I think these genes are so popular because male warblers use these carotenoid colors to attract females that have a discerning eye. Male birds obtain carotenoids from the insects they eat<\/a>. The idea is that the more colorful a male is, the higher the quality of its diet.<\/p>\n\n\n\n

From across the forest, the males\u2019 rich carotenoid colors are signaling that they\u2019d be good dads with good genes. Biologists call this kind of display an \u201chonest signal<\/a>.\u201d And if males obtain a new gene that allows them to process carotenoids more efficiently, it\u2019s likely to spread faster and farther into the species, as the brighter males will potentially have greater mating success.<\/p>\n\n\n\n

Our research with warblers demonstrates how evolution can shuffle genes across the thin lines between species. These close evolutionary neighbors sometimes share DNA, including potentially beneficial mutations, by mating across the species lines defined by humans\u2019 classification systems.<\/p>\n\n\n\n

We suspect that the more we look, the more we\u2019ll find this kind of borrowing among evolutionary neighbors. As we unravel the stories told in the genomes of nature\u2019s problem-solvers, it\u2019s likely we\u2019ll find that their threads are deeply intertwined.<\/p>\n\n\n\n

David Toews<\/a>, Associate Professor of Biology, Penn State<\/a><\/em><\/p>\n\n\n\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

David Toews, Penn State People typically think about evolution as a linear process where, within a species, the classic adage of \u201csurvival of the fittest\u201d is constantly at play. New DNA mutations arise and get passed from parents to offspring. If any genetic changes prove to be beneficial, they might give those young a survival […]<\/p>\n","protected":false},"author":56,"featured_media":41245,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[8025,292,1862,42,10,118,3410],"tags":[312,1939,2058,5043,885,891,886,860,4887,17225,15373],"_links":{"self":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/41244"}],"collection":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/users\/56"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/comments?post=41244"}],"version-history":[{"count":2,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/41244\/revisions"}],"predecessor-version":[{"id":41348,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/posts\/41244\/revisions\/41348"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media\/41245"}],"wp:attachment":[{"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/media?parent=41244"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/categories?post=41244"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifeandnews.com\/articles\/wp-json\/wp\/v2\/tags?post=41244"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}