Bhashya
अथेदानीं समस्तप्रवचनवंशः स्त्रीप्राधान्यात् ।गुणवा-न्पुत्रो भवतीति प्रस्तुतम्; अतः स्त्रीविशेषणेनैव पुत्रविशेष-णात् आचार्यपरम्परा कीर्त्यते ।तानीमानि शुक्लानीति अ-व्यामिश्राणि ब्राह्मणेन ।अथवा यानीमानि यजूंषि तानिशुक्लानि शुद्धानीत्येतत् ।प्रजापतिमारभ्य यावत्पौतिमाषी-पुत्रः, तावन् अधोमुखो नियताचार्यपूर्वक्रमो वंशः समानम्आ सांजीवीपुत्रान्; ब्रह्मणः प्रवचनाख्यस्य; तच्चैतत् ब्रह्मप्रजापतिप्रबन्धपरम्परया आगत्य अस्मास्वनेकधा विप्रसृतम्अनाद्यनन्तं स्वयंभु ब्रह्म नित्यम्; तस्मै ब्रह्मणे नमः ।नमस्तदनुवर्तिभ्यो गुरुभ्यः ॥
In plain words
Here, at the end, the whole teaching-lineage is traced through the mothers, because the point just made was that a virtuous mother bears a virtuous son — so the succession of teachers is named by what qualifies the mother, since that is what determines the son. When it says 'these are white,' it means: kept clear of the explanatory prose portions. Or, read another way, it simply means the Yajus verses are 'white' — that is, pure. From Prajāpati down to Pautimāṣī's son, that is one unbroken line of teachers, listed in strict order; a parallel line runs down to the sons of Sāñjīvī, both belonging to this teaching called Brahman. And that same Brahman, carried down through Prajāpati's own succession, has spread out among us in countless branches — beginningless, endless, uncaused, eternal. Homage to that Brahman. Homage to the teachers who carry it on.
Close to the Sanskrit
Now, at this point, the entire teaching-lineage [is given] on account of the primacy of the woman; [because] it was stated that 'a virtuous son is born [of such a mother]' — therefore, by the very qualification of the woman — since the son's qualification follows from it — the succession of teachers is proclaimed. 'These are white' [means] unmixed with the Brāhmaṇa [prose]. Or else, whichever Yajus-verses these are, those are 'white,' that is, 'pure' — this is the sense. Beginning from Prajāpati up to Pautimāṣīputra, that much is the lineage facing downward, in a fixed, prior order of teachers; a parallel one [runs] up to the sons of Sāñjīvī, belonging to the teaching called Brahman. And that same Brahman, having come down by the unbroken succession of Prajāpati's line, has spread among us in many branches — the beginningless, endless, self-existent, eternal Brahman; to that Brahman, salutation. Salutation to the teachers who carry it forward.