So, the expected evolutionary history is that gene duplication of the c-lysozyme was followed by mutation, resulting in the loss of lysozyme catalytic activity in α-lactalbumin.
sˈoʊ, ðɪ ɛkspˈɛktᵻd ˌɛvəlˈuːʃənˌɛɹi hˈɪstɚɹi ɪz ðæt dʒˈiːn dˌuːplɪkˈeɪʃən ʌvðə sˈiːlˈaɪsəzˌaɪm wʌz fˈɑːloʊd baɪ mjuːtˈeɪʃən, ɹɪzˈʌltɪŋ ɪnðə lˈɔs ʌv lˈaɪsəzˌaɪm kˌæɾɐlˈɪɾɪk æktˈɪvᵻɾi ɪn ˈælfəlˈæktɐlbjˌuːmɪn.