{"id":519,"date":"2023-11-27T21:28:33","date_gmt":"2023-11-27T21:28:33","guid":{"rendered":"https:\/\/cellandcelldivision.com\/?p=519"},"modified":"2023-11-27T21:28:33","modified_gmt":"2023-11-27T21:28:33","slug":"page-81","status":"publish","type":"post","link":"https:\/\/cellandcelldivision.com\/?p=519","title":{"rendered":"Page 81"},"content":{"rendered":"\n<h2 class=\"wp-block-heading has-text-align-center\">Chromosome Theory of Heredity and Organization of the Genome<\/h2>\n\n\n\n<p class=\"has-text-align-center\"><strong>Section 2.6.<\/strong> The chromosome theory of heredity is one of the great<br>achievements in biology. The rules of inheriting the features in the next<br>generations discovered by Mendel have laid the ground for its buildup and<br>further development. In his time these discoveries have not found their due<br>explanation since cell division and meiosis responsible for the formation of<br>the gametes (i.e. the sexual cells) taking part in the fertilization have not<br>been known yet (see Chapter 3, Section 3. 2 and 3. 4).<br>In 1884 K. N\u00e4geli has admitted hypothetically the existence of<br><strong>idioplasm<\/strong> as a specific hereditary substance. Almost simultaneously E.<br>van Beneden, E. Strasburger, O. Hertwig, R. K\u00f6llicker, A. Weissmann,<br>etc. have come to the conclusion that N\u00e4geli\u2019s idioplasm could be found<br>in the chromosomes.<br>The chromosome-heredity link has greatly captured the imagination of<br>many researchers. The cytological studies on the behaviour of the<br>chromosomes, in the process of cell division and meiosis have shown that<br>the sexual cells \u2014 spermatozoa and eggs \u2014 possess a single (haploid) set<br>of chromosomes and the fertilized ones \u2014 the zygotes, contain a double<br>(diploid) set of chromosomes. T. Boveri and W. Sutton have related these<br>results to the rules observed by Mendel in the inheritance of the features in<br>the process of hybridization in peas.<br>In his classical paper \u201cThe Chromosomes in Heredity\u201d the American<br>biologist W. Sutton (1903) has for the first time paid attention to the fact that<br>the diploid chromosome set consist of two morphologically similar haploid<br>sets of chromosomes and in the process of meiosis the gametes receive<br>one haploid chromosome from each homologous pair. He has made the<br>assumption that the genes are a part of the chromosomes, and being<br>based on the data available at that time from the cytological studies has<br>explained some of Mendel\u2019s results in the hybridization. This work has<br>played a great role in the creation of the chromosome theory and in<br>connecting the cytology with genetics.<br>The view that heredity is to be found in the chromosomes and the<br>chromosome number is specific and exactly determined for each separate<br>species of organisms has been already shared by most of the researchers.<br>Around 1890, however, a chromosome has been discovered which was not<br>always observed in two copies in the cells. This chromosome was<br>interpreted as an additional or sexual chromosome (McClung, 1901) and<br>has later become known as <strong>X-chromosome<\/strong>. Its significance has been<br>clarified by E. Wilson and his student Stevens. They have assumed that<br>there are normally two X-chromosomes in the cells of the female individuals<br>and in the cells of the male individuals \u2014 only one. Besides, it has been<br>established that in some species (the human including) yet another<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Chromosome Theory of Heredity and Organization of the Genome Section 2.6. The chromosome theory of heredity is one of the greatachievements in biology. The rules of inheriting the features in the nextgenerations discovered by Mendel have laid the ground for its buildup andfurther development. In his time these discoveries have not found their dueexplanation since [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","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":"","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":"set","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":[6],"tags":[],"class_list":["post-519","post","type-post","status-publish","format-standard","hentry","category-book"],"_links":{"self":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/519","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=519"}],"version-history":[{"count":1,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/519\/revisions"}],"predecessor-version":[{"id":529,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=\/wp\/v2\/posts\/519\/revisions\/529"}],"wp:attachment":[{"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=519"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=519"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cellandcelldivision.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=519"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}