{"id":239867,"date":"2025-07-03T05:48:53","date_gmt":"2025-07-03T05:48:53","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=239867"},"modified":"2025-07-03T05:48:56","modified_gmt":"2025-07-03T05:48:56","slug":"a-woman-is-phenotypically-normal-but-her-father-had-the-sex-linked-recessive-condition-of-red-green-color-blindness","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/03\/a-woman-is-phenotypically-normal-but-her-father-had-the-sex-linked-recessive-condition-of-red-green-color-blindness\/","title":{"rendered":"A woman is phenotypically normal, but her father had the sex-linked recessive condition of red-green color blindness"},"content":{"rendered":"\n<p>A woman is phenotypically normal, but her father had the sex-linked recessive condition of red-green color blindness. If she marries a man with normal vision, a. What is the probability that they will have a color blind son? b. What is the probability that they will have a color blind daughter? c. what is the probability that their two children will both have normal vision? d. what is the probability that their first child will have normal vision and their second child will be color blind?<\/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<h3 class=\"wp-block-heading\">a. Probability that they will have a color blind son<\/h3>\n\n\n\n<p>To solve this, we first need to understand the genetic inheritance pattern for color blindness, which is a sex-linked recessive trait located on the X chromosome. The father of the woman is color blind, which means his genotype is X\u1d04Y (where X\u1d04 represents the X chromosome carrying the color blind allele, and Y is the Y chromosome). The woman has normal vision but carries the allele for color blindness, so her genotype is X\u1d04X (heterozygous).<\/p>\n\n\n\n<p>When she marries a man with normal vision, his genotype is X\u1d3aY (where X\u1d3a is the normal X chromosome and Y is the Y chromosome). The possible combinations for their children are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sons inherit their Y chromosome from their father and one of the X chromosomes from their mother. The son could inherit either X\u1d04 or X\u1d3a from his mother.<\/li>\n\n\n\n<li>Daughters inherit one X chromosome from each parent. Since the father only contributes X\u1d3a, the daughter will inherit one X\u1d3a from him and one X\u1d04 or X\u1d3a from her mother.<\/li>\n<\/ul>\n\n\n\n<p>For a son to be color blind, he must inherit the X\u1d04 chromosome from his mother (because males have only one X chromosome). So, the probability of having a color blind son is <strong>50%<\/strong> (since there is a 50% chance the son will inherit X\u1d04).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">b. Probability that they will have a color blind daughter<\/h3>\n\n\n\n<p>For a daughter to be color blind, she would need to inherit the X\u1d04 chromosome from both parents. The father contributes only a normal X\u1d3a chromosome to his daughters. Therefore, it is <strong>impossible<\/strong> for the daughter to be color blind because she cannot inherit a color blind X from her father.<\/p>\n\n\n\n<p>Thus, the probability of having a color blind daughter is <strong>0%<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">c. Probability that their two children will both have normal vision<\/h3>\n\n\n\n<p>The probability of having a child with normal vision depends on the combination of X chromosomes they inherit. For a son to have normal vision, he must inherit X\u1d3a from his mother, and for a daughter to have normal vision, she must inherit at least one X\u1d3a from each parent.<\/p>\n\n\n\n<p>For each child, the probability of normal vision is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Sons<\/strong>: 50% chance of inheriting X\u1d3a from their mother (since there are two options: X\u1d04 or X\u1d3a).<\/li>\n\n\n\n<li><strong>Daughters<\/strong>: 100% chance of having normal vision, because they will inherit X\u1d3a from their father and either X\u1d04 or X\u1d3a from their mother.<\/li>\n<\/ul>\n\n\n\n<p>So, the probability of both children having normal vision (whether one is a son or daughter) is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>50%<\/strong> (normal son) \u00d7 <strong>100%<\/strong> (normal daughter) = <strong>50%<\/strong>.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">d. Probability that their first child will have normal vision and their second child will be color blind<\/h3>\n\n\n\n<p>For the first child to have normal vision, the probabilities are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Sons<\/strong>: 50% chance of normal vision (inherits X\u1d3a from mother).<\/li>\n\n\n\n<li><strong>Daughters<\/strong>: 100% chance of normal vision.<\/li>\n<\/ul>\n\n\n\n<p>For the second child to be color blind, the probabilities are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Sons<\/strong>: 50% chance of color blindness (inherits X\u1d04 from mother).<\/li>\n\n\n\n<li><strong>Daughters<\/strong>: 0% chance of color blindness (since they inherit only normal X chromosomes from father).<\/li>\n<\/ul>\n\n\n\n<p>Thus, the probability that the first child will have normal vision and the second will be color blind is:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>50%<\/strong> (first son with normal vision) \u00d7 <strong>50%<\/strong> (second son with color blindness) = <strong>25%<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p>In conclusion, the correct answers are:<\/p>\n\n\n\n<p>a. 50%<br>b. 0%<br>c. 50%<br>d. 25%<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A woman is phenotypically normal, but her father had the sex-linked recessive condition of red-green color blindness. If she marries a man with normal vision, a. What is the probability that they will have a color blind son? b. What is the probability that they will have a color blind daughter? c. what is the [&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-239867","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/239867","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=239867"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/239867\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=239867"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=239867"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=239867"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}