{"id":281569,"date":"2025-10-06T11:16:12","date_gmt":"2025-10-06T11:16:12","guid":{"rendered":"https:\/\/www.europesays.com\/us\/281569\/"},"modified":"2025-10-06T11:16:12","modified_gmt":"2025-10-06T11:16:12","slug":"an-ancient-infection-may-play-a-critical-role-in-our-first-moments-of-life-sciencealert","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/281569\/","title":{"rendered":"An Ancient Infection May Play a Critical Role in Our First Moments of Life : ScienceAlert"},"content":{"rendered":"

Fragments of DNA left by viruses<\/a> that infected our distant ancestors may be ‘firestarters’ for new human life, new research finds.<\/p>\n

“Our results illustrate how recently emerged\u2026 genes can confer developmentally essential functions in humans,” Stanford University biologist Raquel Fueyo and colleagues write<\/a> in their paper.<\/p>\n

Fueyo and her team used a ball of stem cells induced to mimic a blastocyst<\/a>, the phase of embryonic development about five days after fertilization. This 3D model<\/a>, or blastoid, replicates the developmental stage just before the embryo implants into the uterus’s lining.<\/p>\n

When the researchers disabled a group of remnant virus<\/a> genes known as LTR5Hs, the embryonic model either turned into a disorganized clump of cells or died. Without the LTR5Hs, the middle layer (epiblast) of the three-tissue-layered blastoid did not form properly.<\/p>\n

Related: ‘Pause Button’ Molecule Uncovered in Human Embryos<\/a><\/strong><\/p>\n

\"YouTube frameborder=”0\u2033 allow=”accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen><\/p>\n

Up to 9 percent of our DNA is composed of genetic material from ancient viral invaders. These endogenous retrovirus<\/a> remnants infiltrated the genetic material of our ancestors’ reproductive cells millions of years ago and are now permanently integrated into our genetic blueprints.<\/p>\n

LTR5Hs appeared in our ancestral line around 5 million years ago, after humans and other great apes had parted ways with ‘old world’ monkeys such as baboons and macaques.<\/p>\n

While this may seem like a long time ago, by evolutionary standards this is a relatively recent change in our genome.<\/p>\n

\u00a0<\/p>\n

\"DiagramBy day nine, the embryo should have three distinct tissue layers, but without LTR5Hs, researchers found, the middle layer didn’t form properly. (Panzer VI-II\/Wikipedia\/CC By SA 3.0<\/a>)<\/p>\n

“Many of the LTR5Hs genomic insertions in the human genome are unique to our own species,” Fueyo and team explain<\/a>.<\/p>\n

“We have shown that [LTR5Hs] activity is required for blastoid formation and lineage identity.”<\/p>\n

The researchers found that this regulatory gene is responsible for increasing the expression of other nearby sequences, including a gene known as ZNF729 that plays a key role in stem cell multiplication and determining cell identity. Low expression of ZNF729 leads to an entire layer of embryonic tissue forming incorrectly.<\/p>\n

The team suspects that by boosting ZNF729, the LTR5H gene group made it more ‘sticky’, giving our ancestors a significant evolutionary advantage.<\/p>\n

“These observations suggest that evolutionary remodeling of gene-regulatory networks can result not only in species-specific innovation but also create new dependencies and bestow essentiality on recently emerged [regulatory] elements and genes,” the researchers conclude<\/a>.<\/p>\n

This research was published in Nature<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"Fragments of DNA left by viruses that infected our distant ancestors may be ‘firestarters’ for new human life,…\n","protected":false},"author":3,"featured_media":281570,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[815,352,159,67,132,68],"class_list":{"0":"post-281569","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-genetics","8":"tag-genetics","9":"tag-msft-content","10":"tag-science","11":"tag-united-states","12":"tag-unitedstates","13":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115326942402347625","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/281569","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=281569"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/281569\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/281570"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=281569"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=281569"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=281569"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}