don't map to the size

app.py

@@ -71,7 +71,7 @@ chart_data = pd.DataFrame({
     "expression_1": np.log10(estimated_expression.loc[h99_transcript_annotations["gene_id"] == gene_id_1].to_numpy()[0] + 1),
     "expression_2": np.log10(estimated_expression.loc[h99_transcript_annotations["gene_id"] == gene_id_2].to_numpy()[0] + 1),
     "run_accession": estimated_expression.columns})
-chart_data.merge(
+chart_data = chart_data.merge(
     right = estimated_expression_meta,
     on = "run_accession")
 
@@ -81,7 +81,6 @@ chart = (
    .encode(
        x="expression_1",
        y="expression_2",
-       size=5,
        color="study_accession",
        tooltip=["run_accession", "study_accession"]))