{"id":165445,"date":"2024-11-12T09:29:04","date_gmt":"2024-11-12T09:29:04","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=165445"},"modified":"2024-11-12T09:29:06","modified_gmt":"2024-11-12T09:29:06","slug":"the-9331-ratio-is-obtained","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2024\/11\/12\/the-9331-ratio-is-obtained\/","title":{"rendered":"The 9:3:3:1 ratio is obtained"},"content":{"rendered":"\n

The 9:3:3:1 ratio is obtained<\/p>\n\n\n\n

a) All of the above b) In a dihybrid cross in which the genes are linked on the same chromosome c) In a dihybrid cross in which the genes are on different chromosomes d) When crossing over occurs<\/p>\n\n\n\n

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

The correct answer is c) In a dihybrid cross in which the genes are on different chromosomes.<\/strong><\/p>\n\n\n\n

Explanation:<\/h3>\n\n\n\n

The 9:3:3:1 ratio is typically observed in a dihybrid cross<\/strong> where two traits are being studied, and the genes for those traits are located on different chromosomes<\/strong>. This ratio arises when the genes assort independently, a principle known as Mendel\u2019s Law of Independent Assortment<\/strong>. This law states that alleles for different traits segregate independently during the formation of gametes.<\/p>\n\n\n\n

In a typical dihybrid cross, two individuals are crossed, each heterozygous for two traits, which are represented by two pairs of alleles (e.g., AaBb x AaBb). When the genes for the two traits are located on different chromosomes, the alleles for each gene segregate independently during gamete formation. This independent assortment results in four possible combinations of alleles in the offspring, and when the offspring are counted, the expected phenotypic ratio is 9:3:3:1.<\/p>\n\n\n\n

    \n
  • The 9 represents the offspring that inherit both dominant traits.<\/li>\n\n\n\n
  • The 3’s represent the offspring inheriting one dominant trait and one recessive trait.<\/li>\n\n\n\n
  • The 1 represents the offspring inheriting both recessive traits.<\/li>\n<\/ul>\n\n\n\n

    Why the other options are incorrect:<\/h4>\n\n\n\n
      \n
    • a) All of the above<\/strong>: This option is not correct because the 9:3:3:1 ratio does not apply to all of the scenarios described in the other choices.<\/li>\n\n\n\n
    • b) In a dihybrid cross in which the genes are linked on the same chromosome<\/strong>: When genes are linked on the same chromosome, they tend to be inherited together and do not assort independently. This leads to a different genetic ratio, not 9:3:3:1. Typically, linked genes show a less diverse<\/strong> set of offspring, and crossing over may create a different set of recombinants.<\/li>\n\n\n\n
    • d) When crossing over occurs<\/strong>: While crossing over can influence the genetic variation in the offspring, it does not directly result in a 9:3:3:1 ratio. Crossing over occurs between homologous chromosomes during meiosis, and the occurrence of recombination can affect the inheritance of linked genes. However, the 9:3:3:1 ratio specifically reflects independent assortment when genes are on different chromosomes, rather than the effects of crossing over alone.<\/li>\n<\/ul>\n\n\n\n

      Therefore, the correct answer is c<\/strong>, as independent assortment in a dihybrid cross involving genes on different chromosomes results in the 9:3:3:1 phenotypic ratio.<\/p>\n","protected":false},"excerpt":{"rendered":"

      The 9:3:3:1 ratio is obtained a) All of the above b) In a dihybrid cross in which the genes are linked on the same chromosome c) In a dihybrid cross in which the genes are on different chromosomes d) When crossing over occurs The Correct Answer and Explanation is: The correct answer is c) In […]<\/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-165445","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/165445","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=165445"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/165445\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=165445"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=165445"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=165445"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}