Order result from ajax

So you can use the prepend method:

 <script>
  $(document).ready(function(){

      var ajaxurl = "<?php echo admin_url( 'admin-ajax.php' ); ?>";   
      var dataArray =  <?php echo json_encode($current_posts_ids) ?>;

      function getMyPosts() {

            data = { action: "update_news", data: dataArray};
            $.post(ajaxurl, data, function(response) {
                // reset array
                dataArray = [];
                // append the new news posts                
                $('.latest-news .posts').prepend(response);
                // create new array of ids to exclude
                $('article').each(function(){
                    dataArray.push($(this).data('id'));  
                }); 
                // repeat function after 5 seconds
                setTimeout(function () {
                    getMyPosts();
                }, 5000)
            });

     }
     //run the function first time
     getMyPosts();   

});
</script>