{"id":170035,"date":"2024-11-19T15:55:36","date_gmt":"2024-11-19T15:55:36","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=170035"},"modified":"2024-11-19T15:55:38","modified_gmt":"2024-11-19T15:55:38","slug":"in-labrador-retrievers-two-genes-determine-fur-color","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2024\/11\/19\/in-labrador-retrievers-two-genes-determine-fur-color\/","title":{"rendered":"In Labrador retrievers, two genes determine fur color"},"content":{"rendered":"\n<p>In Labrador retrievers, two genes determine fur color: the E gene and the B gene. Black fur (B) is dominant to brown fur (b). However, the presence of (ee) will overshadow and create a puppy with yellow fur. Create a Punnett square crossing 2 Labs that are heterozygous for both genes. Then color code your Punnett Square based on the resulting phenotypes. Don&#8217;t forget to take epistasis into account! Determine the phenotypic ratio.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>Let&#8217;s break down the genetic cross involving Labrador retrievers and the two genes that determine fur color: the <strong>E gene<\/strong> and the <strong>B gene<\/strong>.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>B (black)<\/strong> is dominant to <strong>b (brown)<\/strong>.<\/li>\n\n\n\n<li><strong>E (dominant)<\/strong> allows fur color to be expressed, while the <strong>ee (recessive)<\/strong> genotype will result in yellow fur, regardless of the B gene alleles. This is an example of <strong>epistasis<\/strong>, where the E gene overrides the effects of the B gene.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Parent Genotypes:<\/h3>\n\n\n\n<p>We are crossing two Labrador retrievers that are both heterozygous for both genes. Therefore, each parent\u2019s genotype is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>BbEe<\/strong> (heterozygous for both the B and E genes).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Punnett Square:<\/h3>\n\n\n\n<p>To create the Punnett square, we\u2019ll combine the alleles from both parents. Each parent can pass on one allele for the <strong>B<\/strong> gene and one allele for the <strong>E<\/strong> gene. Thus, the possible gametes are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>BE<\/strong><\/li>\n\n\n\n<li><strong>Be<\/strong><\/li>\n\n\n\n<li><strong>bE<\/strong><\/li>\n\n\n\n<li><strong>be<\/strong><\/li>\n<\/ul>\n\n\n\n<p>Let\u2019s set up the Punnett square with these four possible gametes from each parent:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><\/th><th>BE<\/th><th>Be<\/th><th>bE<\/th><th>be<\/th><\/tr><\/thead><tbody><tr><td><strong>BE<\/strong><\/td><td>BBEe<\/td><td>BBEe<\/td><td>BbEe<\/td><td>BbEe<\/td><\/tr><tr><td><strong>Be<\/strong><\/td><td>BBEe<\/td><td>BBEe<\/td><td>BbEe<\/td><td>BbEe<\/td><\/tr><tr><td><strong>bE<\/strong><\/td><td>BbEe<\/td><td>BbEe<\/td><td>bbEe<\/td><td>bbEe<\/td><\/tr><tr><td><strong>be<\/strong><\/td><td>BbEe<\/td><td>BbEe<\/td><td>bbEe<\/td><td>bbEe<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Phenotype Determination:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>BB or Bb<\/strong> (black fur): If there is at least one B allele and at least one E allele (<strong>Ee<\/strong>, <strong>EE<\/strong>, or <strong>ee<\/strong>), the dog will have black fur.<\/li>\n\n\n\n<li><strong>bb<\/strong> (brown fur): If there are two <strong>b<\/strong> alleles and at least one <strong>E<\/strong> allele (<strong>Ee<\/strong> or <strong>EE<\/strong>), the dog will have brown fur.<\/li>\n\n\n\n<li><strong>ee<\/strong> (yellow fur): If the dog has the <strong>ee<\/strong> genotype, regardless of the <strong>B<\/strong> or <strong>b<\/strong> alleles, the dog will have yellow fur due to epistasis.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Phenotypic Color Mapping:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Black Fur<\/strong>: Any combination with at least one B allele and at least one E allele (BBEE, BBEe, BbEE, BbEe).<\/li>\n\n\n\n<li><strong>Brown Fur<\/strong>: bbEE or bbEe.<\/li>\n\n\n\n<li><strong>Yellow Fur<\/strong>: ee (regardless of B or b alleles).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Results of the Punnett Square:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Black Fur<\/strong>: 9 outcomes (BBEE, BBEe, BbEE, BbEe).<\/li>\n\n\n\n<li><strong>Brown Fur<\/strong>: 2 outcomes (bbEE, bbEe).<\/li>\n\n\n\n<li><strong>Yellow Fur<\/strong>: 4 outcomes (any with ee).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Phenotypic Ratio:<\/h3>\n\n\n\n<p>The phenotypic ratio from this cross is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>9 Black<\/strong> : <strong>3 Brown<\/strong> : <strong>4 Yellow<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p>This ratio reflects the combined effects of both the B and E genes, with epistasis from the <strong>ee<\/strong> genotype taking precedence and causing yellow fur in a significant proportion of the offspring.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In Labrador retrievers, two genes determine fur color: the E gene and the B gene. Black fur (B) is dominant to brown fur (b). However, the presence of (ee) will overshadow and create a puppy with yellow fur. Create a Punnett square crossing 2 Labs that are heterozygous for both genes. Then color code your [&hellip;]<\/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-170035","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/170035","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=170035"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/170035\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=170035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=170035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=170035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}