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  • Evolution of Mammary Glands


    Mammary glands, distinctive in mammals evolved by co-opting existing molecular network used in body patterning; these are the findings reported by Schep in a recent paper published in PNAS.

    Authors report Hox, the regulatory networks (mentioned in this thread) involved in embryonic limb patterning and development were co-opted for the formation of mammary glands.

    The authors found mammary gland requires the enhancer Mammary bud regulatory element to activate Hoxd9, a subset of HoxD. The thing is that MB regulatory network is found in all tissues. This suggest MB predates the development of mammary tissue (unless the creo god is really into breast tissue) and evolution was able to use existing molecular networks to create new tissue types.


    And a final observation to tie it in with other threads; placodes, also involved in the formation of scales, feathers and hair play a vital role in the development of mammary glands. The paper describes the process "At embryonic day (E) 11.5, the murine milk lines split into five symmetrical pairs of mammary placodes (MPs). Each placode is associated with a specialized underlying mammary mesenchyme, which drives mammary ectoderm invagination and formation of the duct system. By E12.5, the placodes invaginate, and around E13.5, they form the mammary buds (MBs), which will then elongate and sprout to create a ductular structure deeper in the dermal mesenchyme."

    So we have two different examples of evolution using existing systems to create mammary glands; placodes - common to reptiles, birds and mammals - and Hox9 networks involved in body patterning.




    Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

    Significance

    During vertebrate evolution, Hox gene function was coopted through the emergence of global enhancers outside the Hox gene clusters. Here, we analyze the regulatory modalities underlying Hoxd gene transcription into the developing mammary glands where Hox proteins are necessary. We report the existence of a long-distance acting mammary bud enhancer located near sequences involved in controlling Hox genes in the limbs. We argue that the particular constitutive chromatin structure found at this locus facilitated the emergence of this enhancer element in mammals by hijacking a regulatory context at work in other cell types, supporting a model wherein enhancer sequences tend to cluster into large regulatory landscapes due to an increased probability to evolve within a preexisting regulatory structure.
    Abstract

    Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.

    "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

  • #2
    Originally posted by Promethean View Post
    Mammary glands, distinctive in mammals evolved by co-opting existing molecular network used in body patterning; these are the findings reported by Schep in a recent paper published in PNAS.

    Authors report Hox, the regulatory networks (mentioned in this thread) involved in embryonic limb patterning and development were co-opted for the formation of mammary glands.

    The authors found mammary gland requires the enhancer Mammary bud regulatory element to activate Hoxd9, a subset of HoxD. The thing is that MB regulatory network is found in all tissues. This suggest MB predates the development of mammary tissue (unless the creo god is really into breast tissue) and evolution was able to use existing molecular networks to create new tissue types.


    And a final observation to tie it in with other threads; placodes, also involved in the formation of scales, feathers and hair play a vital role in the development of mammary glands. The paper describes the process "At embryonic day (E) 11.5, the murine milk lines split into five symmetrical pairs of mammary placodes (MPs). Each placode is associated with a specialized underlying mammary mesenchyme, which drives mammary ectoderm invagination and formation of the duct system. By E12.5, the placodes invaginate, and around E13.5, they form the mammary buds (MBs), which will then elongate and sprout to create a ductular structure deeper in the dermal mesenchyme."

    So we have two different examples of evolution using existing systems to create mammary glands; placodes - common to reptiles, birds and mammals - and Hox9 networks involved in body patterning.




    Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

    Significance

    During vertebrate evolution, Hox gene function was coopted through the emergence of global enhancers outside the Hox gene clusters. Here, we analyze the regulatory modalities underlying Hoxd gene transcription into the developing mammary glands where Hox proteins are necessary. We report the existence of a long-distance acting mammary bud enhancer located near sequences involved in controlling Hox genes in the limbs. We argue that the particular constitutive chromatin structure found at this locus facilitated the emergence of this enhancer element in mammals by hijacking a regulatory context at work in other cell types, supporting a model wherein enhancer sequences tend to cluster into large regulatory landscapes due to an increased probability to evolve within a preexisting regulatory structure.
    Abstract

    Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.
    Myth of Prometheus.

    God created mammals and humans at the beginning with mammary glands. Myths and speculations fail again. Your fossil thumper works fail. It boggles the human mind how intrigued locals are with their imagination driven narratives.

    Comment


    • #3
      Originally posted by Nouveau View Post

      Myth of Prometheus.

      God created mammals and humans at the beginning with mammary glands. Myths and speculations fail again. Your fossil thumper works fail. It boggles the human mind how intrigued locals are with their imagination driven narratives.
      This OP makes it clear creos are noobs and b00bs
      "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

      Comment


      • #4
        Originally posted by Nouveau View Post

        Myth of Prometheus.

        God created mammals and humans at the beginning with mammary glands.
        The myth of YAWEH. Why did your little god make it so that all tissues present mammary gland network?

        Why did your little god use the same system to make limbs to make mammary tissue?

        Why did your little god use the same placodes that make hair and feathers to make mammary tissue?

        Myths and speculations fail again. Your fossil thumper works fail. It boggles the human mind how intrigued locals are with their imagination driven narratives.
        Vacuous creo proclamations fail because creationism is a failure.

        "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

        Comment


        • #5
          Originally posted by Promethean View Post
          Mammary glands, distinctive in mammals evolved by co-opting existing molecular network used in body patterning; these are the findings reported by Schep in a recent paper published in PNAS.

          Authors report Hox, the regulatory networks (mentioned in this thread) involved in embryonic limb patterning and development were co-opted for the formation of mammary glands.

          The authors found mammary gland requires the enhancer Mammary bud regulatory element to activate Hoxd9, a subset of HoxD. The thing is that MB regulatory network is found in all tissues. This suggest MB predates the development of mammary tissue (unless the creo god is really into breast tissue) and evolution was able to use existing molecular networks to create new tissue types.


          And a final observation to tie it in with other threads; placodes, also involved in the formation of scales, feathers and hair play a vital role in the development of mammary glands. The paper describes the process "At embryonic day (E) 11.5, the murine milk lines split into five symmetrical pairs of mammary placodes (MPs). Each placode is associated with a specialized underlying mammary mesenchyme, which drives mammary ectoderm invagination and formation of the duct system. By E12.5, the placodes invaginate, and around E13.5, they form the mammary buds (MBs), which will then elongate and sprout to create a ductular structure deeper in the dermal mesenchyme."

          So we have two different examples of evolution using existing systems to create mammary glands; placodes - common to reptiles, birds and mammals - and Hox9 networks involved in body patterning.




          Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

          Significance

          During vertebrate evolution, Hox gene function was coopted through the emergence of global enhancers outside the Hox gene clusters. Here, we analyze the regulatory modalities underlying Hoxd gene transcription into the developing mammary glands where Hox proteins are necessary. We report the existence of a long-distance acting mammary bud enhancer located near sequences involved in controlling Hox genes in the limbs. We argue that the particular constitutive chromatin structure found at this locus facilitated the emergence of this enhancer element in mammals by hijacking a regulatory context at work in other cell types, supporting a model wherein enhancer sequences tend to cluster into large regulatory landscapes due to an increased probability to evolve within a preexisting regulatory structure.
          Abstract

          Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.
          So while I want to discuss Hox genes and regulation of development the creo noob (or should that n be a b?) writes about a god he's never seen.
          "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

          Comment


          • #6
            Originally posted by Nouveau View Post

            Myth of Prometheus.

            God created mammals and humans at the beginning with mammary glands. Myths and speculations fail again. Your fossil thumper works fail. It boggles the human mind how intrigued locals are with their imagination driven narratives.
            Calling this leg lifting would demean dogs, who are much more intelligent and intellectual than YECs

            Comment


            • #7
              Originally posted by Nouveau View Post

              Myth of Prometheus.
              Total non-sequitur again, as usual.


              When evil is powerful, good men are silenced.

              Comment


              • #8
                Originally posted by Promethean View Post
                Mammary glands, distinctive in mammals evolved by co-opting existing molecular network used in body patterning; these are the findings reported by Schep in a recent paper published in PNAS.

                Authors report Hox, the regulatory networks (mentioned in this thread) involved in embryonic limb patterning and development were co-opted for the formation of mammary glands.

                The authors found mammary gland requires the enhancer Mammary bud regulatory element to activate Hoxd9, a subset of HoxD. The thing is that MB regulatory network is found in all tissues. This suggest MB predates the development of mammary tissue (unless the creo god is really into breast tissue) and evolution was able to use existing molecular networks to create new tissue types.


                And a final observation to tie it in with other threads; placodes, also involved in the formation of scales, feathers and hair play a vital role in the development of mammary glands. The paper describes the process "At embryonic day (E) 11.5, the murine milk lines split into five symmetrical pairs of mammary placodes (MPs). Each placode is associated with a specialized underlying mammary mesenchyme, which drives mammary ectoderm invagination and formation of the duct system. By E12.5, the placodes invaginate, and around E13.5, they form the mammary buds (MBs), which will then elongate and sprout to create a ductular structure deeper in the dermal mesenchyme."

                So we have two different examples of evolution using existing systems to create mammary glands; placodes - common to reptiles, birds and mammals - and Hox9 networks involved in body patterning.




                Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

                Significance

                During vertebrate evolution, Hox gene function was coopted through the emergence of global enhancers outside the Hox gene clusters. Here, we analyze the regulatory modalities underlying Hoxd gene transcription into the developing mammary glands where Hox proteins are necessary. We report the existence of a long-distance acting mammary bud enhancer located near sequences involved in controlling Hox genes in the limbs. We argue that the particular constitutive chromatin structure found at this locus facilitated the emergence of this enhancer element in mammals by hijacking a regulatory context at work in other cell types, supporting a model wherein enhancer sequences tend to cluster into large regulatory landscapes due to an increased probability to evolve within a preexisting regulatory structure.
                Abstract

                Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.
                rebump
                "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

                Comment


                • #9
                  Originally posted by Promethean View Post
                  Mammary glands, distinctive in mammals evolved by co-opting existing molecular network used in body patterning; these are the findings reported by Schep in a recent paper published in PNAS.

                  Authors report Hox, the regulatory networks (mentioned in this thread) involved in embryonic limb patterning and development were co-opted for the formation of mammary glands.

                  The authors found mammary gland requires the enhancer Mammary bud regulatory element to activate Hoxd9, a subset of HoxD. The thing is that MB regulatory network is found in all tissues. This suggest MB predates the development of mammary tissue (unless the creo god is really into breast tissue) and evolution was able to use existing molecular networks to create new tissue types.


                  And a final observation to tie it in with other threads; placodes, also involved in the formation of scales, feathers and hair play a vital role in the development of mammary glands. The paper describes the process "At embryonic day (E) 11.5, the murine milk lines split into five symmetrical pairs of mammary placodes (MPs). Each placode is associated with a specialized underlying mammary mesenchyme, which drives mammary ectoderm invagination and formation of the duct system. By E12.5, the placodes invaginate, and around E13.5, they form the mammary buds (MBs), which will then elongate and sprout to create a ductular structure deeper in the dermal mesenchyme."

                  So we have two different examples of evolution using existing systems to create mammary glands; placodes - common to reptiles, birds and mammals - and Hox9 networks involved in body patterning.




                  Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

                  Significance

                  During vertebrate evolution, Hox gene function was coopted through the emergence of global enhancers outside the Hox gene clusters. Here, we analyze the regulatory modalities underlying Hoxd gene transcription into the developing mammary glands where Hox proteins are necessary. We report the existence of a long-distance acting mammary bud enhancer located near sequences involved in controlling Hox genes in the limbs. We argue that the particular constitutive chromatin structure found at this locus facilitated the emergence of this enhancer element in mammals by hijacking a regulatory context at work in other cell types, supporting a model wherein enhancer sequences tend to cluster into large regulatory landscapes due to an increased probability to evolve within a preexisting regulatory structure.
                  Abstract

                  Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.
                  Gonna milk this thread.
                  "Kids & Adults love Fairy Tale Ark exhibit" - Ken Ham

                  Comment

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