Delete points in a Serial Area from the WPF Toolkit

I have implemented a AreaSerie with toolkit. The problem is that it is marking the points in the graph and I would like to eliminate them. I add an example photo. In the photo is marked the points that I do not want them to be.

And my code is as follows

<chartingToolkit:Chart x:Name="chart" HorizontalAlignment="Left" BorderBrush="White" VerticalAlignment="center" Height="200" Width="397" Grid.Column="0" Grid.Row="0" Margin="4,4,0,-4" >
    <chartingToolkit:Chart.LegendStyle>
        <Style TargetType="Control">
            <Setter Property="Width" Value="0" />
            <Setter Property="Height" Value="0" />
        </Style>
    </chartingToolkit:Chart.LegendStyle>
    <chartingToolkit:AreaSeries Name="ChartUp" DependentValuePath="Value" IndependentValuePath="Key"  IsSelectionEnabled="True" ItemsSource="{Binding ChartUpData}" >
        <chartingToolkit:AreaSeries.DataPointStyle>
            <Style TargetType="chartingToolkit:DataPoint">
                <Setter Property="Background" Value="#ffcf3f" />
            </Style>
        </chartingToolkit:AreaSeries.DataPointStyle>
        <chartingToolkit:AreaSeries.IndependentAxis>
            <chartingToolkit:CategoryAxis Orientation="X" Visibility="Hidden"/>
        </chartingToolkit:AreaSeries.IndependentAxis>
        <chartingToolkit:AreaSeries.DependentRangeAxis>
            <chartingToolkit:LinearAxis Orientation="Y" Visibility="Hidden"/>
        </chartingToolkit:AreaSeries.DependentRangeAxis>
    </chartingToolkit:AreaSeries>
    <chartingToolkit:AreaSeries Name="ChartDown" DependentValuePath="Value" IndependentValuePath="Key" ItemsSource="{Binding ChartDownData}"  IsSelectionEnabled="True">
        <chartingToolkit:AreaSeries.DataPointStyle>
            <Style TargetType="chartingToolkit:DataPoint">
                <Setter Property="Background" Value="#f99b48" />
            </Style>
        </chartingToolkit:AreaSeries.DataPointStyle>
        <chartingToolkit:AreaSeries.IndependentAxis>
            <chartingToolkit:CategoryAxis Orientation="X" Visibility="Hidden"/>
        </chartingToolkit:AreaSeries.IndependentAxis>
        <chartingToolkit:AreaSeries.DependentRangeAxis>
            <chartingToolkit:LinearAxis Orientation="Y" Visibility="Hidden"/>
        </chartingToolkit:AreaSeries.DependentRangeAxis>
    </chartingToolkit:AreaSeries>
</chartingToolkit:Chart>