{"id":222071,"date":"2025-05-31T03:22:16","date_gmt":"2025-05-31T03:22:16","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=222071"},"modified":"2025-05-31T03:22:18","modified_gmt":"2025-05-31T03:22:18","slug":"which-of-the-following-is-true-of-barr-bodies","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/31\/which-of-the-following-is-true-of-barr-bodies\/","title":{"rendered":"Which of the following is true of Barr bodies"},"content":{"rendered":"\n

Which of the following is true of Barr bodies? Choose 1 answer:<\/p>\n\n\n\n

A Barr body is typically found in the nucleus of female gametes.
Barr bodies are chromosomes that are condensed prior to mitosis.
Barr bodies are formed during embryonic development.
A cell that has three X chromosomes will have three Barr bodies.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answer:<\/strong>
Barr bodies are formed during embryonic development.<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation<\/strong><\/h3>\n\n\n\n

Barr bodies are inactivated X chromosomes found in the nuclei of cells in female mammals. They serve as a mechanism for dosage compensation to ensure that females, who have two X chromosomes (XX), do not produce twice the amount of X-linked gene products as males, who have one X chromosome (XY). The process of X-inactivation, also called Lyonization<\/strong>, occurs during early embryonic development<\/strong>, typically in the blastocyst stage. Hence, the correct answer is: “Barr bodies are formed during embryonic development.”<\/strong><\/p>\n\n\n\n

The inactivation of one of the X chromosomes is largely random in each somatic cell (excluding gametes), and once inactivated, the same X chromosome remains inactive in all the progeny cells of that cell. The inactivated X condenses into a compact structure known as a Barr body<\/strong>, which is visible under a microscope near the nuclear envelope.<\/p>\n\n\n\n

Let\u2019s analyze the incorrect options:<\/p>\n\n\n\n

    \n
  • “A Barr body is typically found in the nucleus of female gametes”:<\/strong> False. Female gametes (eggs) do not<\/strong> contain Barr bodies. Gametes are haploid and only have one X chromosome, so there is no need for inactivation.<\/li>\n\n\n\n
  • “Barr bodies are chromosomes that are condensed prior to mitosis”:<\/strong> Incorrect. While chromosomes condense before mitosis, Barr bodies<\/strong> refer specifically to inactivated X chromosomes, not all chromosomes preparing for cell division.<\/li>\n\n\n\n
  • “A cell that has three X chromosomes will have three Barr bodies”:<\/strong> False. In any cell, only one X chromosome remains active<\/strong>, and all the extra X chromosomes are inactivated. So a cell with three X chromosomes (XXX) will have two Barr bodies<\/strong>, not three.<\/li>\n<\/ul>\n\n\n\n

    Therefore, Barr bodies are a key example of epigenetic regulation and are crucial for maintaining gene dosage balance betwee<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n

    n sexes.<\/p>\n","protected":false},"excerpt":{"rendered":"

    Which of the following is true of Barr bodies? Choose 1 answer: A Barr body is typically found in the nucleus of female gametes.Barr bodies are chromosomes that are condensed prior to mitosis.Barr bodies are formed during embryonic development.A cell that has three X chromosomes will have three Barr bodies. The Correct Answer and Explanation […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-222071","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222071","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=222071"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/222071\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=222071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=222071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=222071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}