{"id":2764,"date":"2016-06-13T17:29:02","date_gmt":"2016-06-13T17:29:02","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/biologyxwaymakerxmaster\/?post_type=chapter&#038;p=2764"},"modified":"2017-08-02T16:47:44","modified_gmt":"2017-08-02T16:47:44","slug":"reading-pleiotropy-lethal-alleles-and-sex-linkage","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/chapter\/reading-pleiotropy-lethal-alleles-and-sex-linkage\/","title":{"raw":"Pleiotropy and Human Disorders","rendered":"Pleiotropy and Human Disorders"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\nExplain pleiotropy and its impact on traits in a population\r\n\r\n<\/div>\r\n<h2>Pleiotropy<\/h2>\r\nWhen we discussed Mendel\u2019s experiments with purple-flowered and white-flowered plants, we didn\u2019t mention any other phenotypes associated with the two flower colors. However, Mendel noticed that the flower colors were always correlated with two other features: the color of the seed coat (covering of the seed) and the color of the axils (junctions where the leaves met the main stem)[footnote]Lobo, I. (2008).\r\n\r\n[caption id=\"attachment_2940\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-2940\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/06\/15210254\/pleiotropy.png\" alt=\" Simple schematic illustrating pleiotropy. In pleiotropy, one gene affects multiple features (feature 1, feature 2, feature 3. Caption: One gene affects multiple characteristics.\" width=\"400\" height=\"290\" \/> Based on similar diagram by Ingrid Lobo[\/caption]\r\n\r\nGenes like this, which affect multiple, seemingly unrelated aspects of an organism\u2019s phenotype, are said to be <strong>pleiotropic<\/strong> (<em>pleio<\/em>- = many, -<em>tropic<\/em> = effects)[footnote]<em>Ibid<\/em>.[\/footnote]. The seemingly unrelated phenotypes can all be traced back to a defect in a single gene with several jobs.\r\n\r\nImportantly, alleles of pleiotropic genes are transmitted in the same way as alleles of genes that affect single traits. Although the phenotype has multiple elements, these elements are specified as a package, and the dominant and recessive versions of the package would appear in the progeny of a monohybrid cross in a ratio of\u00a03:1.\r\n<h2>Pleiotropy in Human Genetic Disorders<\/h2>\r\nGenes affected in human genetic disorders are often pleiotropic. For example, people with the hereditary disorder Marfan syndrome may have a constellation of seemingly unrelated symptoms[footnote]Marfan syndrome. (2012). In <em>Genetics home reference<\/em>. Retrieved from\u00a0<a href=\"http:\/\/ghr.nlm.nih.gov\/condition\/marfan-syndrome\" target=\"_blank\" rel=\"noopener\">http:\/\/ghr.nlm.nih.gov\/condition\/marfan-syndrome<\/a>.[\/footnote]:\r\n<ul>\r\n \t<li>Unusually tall height<\/li>\r\n \t<li>Thin fingers and toes<\/li>\r\n \t<li>Dislocation of the lens of the eye<\/li>\r\n \t<li>Heart problems (in which the aorta, the large blood vessel carrying blood away from the heart, bulges or ruptures).<\/li>\r\n<\/ul>\r\nThese symptoms don\u2019t appear directly related to one another, but as it turns out, they can all be traced back to the mutation of a single gene.","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<p>Explain pleiotropy and its impact on traits in a population<\/p>\n<\/div>\n<h2>Pleiotropy<\/h2>\n<p>When we discussed Mendel\u2019s experiments with purple-flowered and white-flowered plants, we didn\u2019t mention any other phenotypes associated with the two flower colors. However, Mendel noticed that the flower colors were always correlated with two other features: the color of the seed coat (covering of the seed) and the color of the axils (junctions where the leaves met the main stem)<a class=\"footnote\" title=\"Lobo, I. (2008).\n\n[caption id=&quot;attachment_2940&quot; align=&quot;alignright&quot; width=&quot;400&quot;] Based on similar diagram by Ingrid Lobo[\/caption]\n\nGenes like this, which affect multiple, seemingly unrelated aspects of an organism\u2019s phenotype, are said to be pleiotropic (pleio- = many, -tropic = effects)[footnote]Ibid.\" id=\"return-footnote-2764-1\" href=\"#footnote-2764-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a>. The seemingly unrelated phenotypes can all be traced back to a defect in a single gene with several jobs.<\/p>\n<p>Importantly, alleles of pleiotropic genes are transmitted in the same way as alleles of genes that affect single traits. Although the phenotype has multiple elements, these elements are specified as a package, and the dominant and recessive versions of the package would appear in the progeny of a monohybrid cross in a ratio of\u00a03:1.<\/p>\n<h2>Pleiotropy in Human Genetic Disorders<\/h2>\n<p>Genes affected in human genetic disorders are often pleiotropic. For example, people with the hereditary disorder Marfan syndrome may have a constellation of seemingly unrelated symptoms<a class=\"footnote\" title=\"Marfan syndrome. (2012). In Genetics home reference. Retrieved from\u00a0http:\/\/ghr.nlm.nih.gov\/condition\/marfan-syndrome.\" id=\"return-footnote-2764-2\" href=\"#footnote-2764-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a>:<\/p>\n<ul>\n<li>Unusually tall height<\/li>\n<li>Thin fingers and toes<\/li>\n<li>Dislocation of the lens of the eye<\/li>\n<li>Heart problems (in which the aorta, the large blood vessel carrying blood away from the heart, bulges or ruptures).<\/li>\n<\/ul>\n<p>These symptoms don\u2019t appear directly related to one another, but as it turns out, they can all be traced back to the mutation of a single gene.<\/p>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2764\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Pleiotropy, lethal alleles, and sex linkage. <strong>Provided by<\/strong>: Khan Academy. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.khanacademy.org\/science\/biology\/classical-genetics\/variations-on-mendelian-genetics\/a\/pleiotropy-lethal-alleles-and-sex-linkage\">https:\/\/www.khanacademy.org\/science\/biology\/classical-genetics\/variations-on-mendelian-genetics\/a\/pleiotropy-lethal-alleles-and-sex-linkage<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/4.0\/\">CC BY-NC-SA: Attribution-NonCommercial-ShareAlike<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section><hr class=\"before-footnotes clear\" \/><div class=\"footnotes\"><ol><li id=\"footnote-2764-1\">Lobo, I. (2008).\r\n\r\n[caption id=\"attachment_2940\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-2940\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/06\/15210254\/pleiotropy.png\" alt=\"Simple schematic illustrating pleiotropy. In pleiotropy, one gene affects multiple features (feature 1, feature 2, feature 3. Caption: One gene affects multiple characteristics.\" width=\"400\" height=\"290\" \/> Based on similar diagram by Ingrid Lobo[\/caption]\r\n\r\nGenes like this, which affect multiple, seemingly unrelated aspects of an organism\u2019s phenotype, are said to be <strong>pleiotropic<\/strong> (<em>pleio<\/em>- = many, -<em>tropic<\/em> = effects)[footnote]<em>Ibid<\/em>. <a href=\"#return-footnote-2764-1\" class=\"return-footnote\" aria-label=\"Return to footnote 1\">&crarr;<\/a><\/li><li id=\"footnote-2764-2\">Marfan syndrome. (2012). In <em>Genetics home reference<\/em>. Retrieved from\u00a0<a href=\"http:\/\/ghr.nlm.nih.gov\/condition\/marfan-syndrome\" target=\"_blank\" rel=\"noopener\">http:\/\/ghr.nlm.nih.gov\/condition\/marfan-syndrome<\/a>. <a href=\"#return-footnote-2764-2\" class=\"return-footnote\" aria-label=\"Return to footnote 2\">&crarr;<\/a><\/li><\/ol><\/div>","protected":false},"author":17,"menu_order":18,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Pleiotropy, lethal alleles, and sex linkage\",\"author\":\"\",\"organization\":\"Khan Academy\",\"url\":\"https:\/\/www.khanacademy.org\/science\/biology\/classical-genetics\/variations-on-mendelian-genetics\/a\/pleiotropy-lethal-alleles-and-sex-linkage\",\"project\":\"\",\"license\":\"cc-by-nc-sa\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"8af89cb3-cf05-41f9-b398-40ff5f20a57b, 193a7251-7ee8-4277-9ece-d8e9ac8af10b","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-2764","chapter","type-chapter","status-publish","hentry"],"part":258,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapters\/2764","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":12,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapters\/2764\/revisions"}],"predecessor-version":[{"id":5342,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapters\/2764\/revisions\/5342"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/parts\/258"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapters\/2764\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/wp\/v2\/media?parent=2764"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/pressbooks\/v2\/chapter-type?post=2764"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/wp\/v2\/contributor?post=2764"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/hccs-waymakerbiology1\/wp-json\/wp\/v2\/license?post=2764"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}