The paper introduces a progressive sequence alignment method that uses the Needleman and Wunsch pairwise alignment algorithm iteratively to construct multiple alignments and evolutionary trees for protein sequences. The method emphasizes the importance of recent evolutionary events over distant ones, following the rule "once a gap, always a gap." This approach is applied to three sets of protein sequences: 7 superoxide dismutases, 11 globins, and 9 tyrosine kinase-like sequences. The resulting phylogenetic trees are compared with those obtained by conventional pairwise methods, showing that the progressive method often aligns more closely with biological expectations. The method is based on maximizing similarities and inserting neutral elements into sequences to maintain gaps, providing a more reliable and objective approach to sequence alignment and tree construction.The paper introduces a progressive sequence alignment method that uses the Needleman and Wunsch pairwise alignment algorithm iteratively to construct multiple alignments and evolutionary trees for protein sequences. The method emphasizes the importance of recent evolutionary events over distant ones, following the rule "once a gap, always a gap." This approach is applied to three sets of protein sequences: 7 superoxide dismutases, 11 globins, and 9 tyrosine kinase-like sequences. The resulting phylogenetic trees are compared with those obtained by conventional pairwise methods, showing that the progressive method often aligns more closely with biological expectations. The method is based on maximizing similarities and inserting neutral elements into sequences to maintain gaps, providing a more reliable and objective approach to sequence alignment and tree construction.