After Dorothy's discussion, I wanted to learn more about the concept and its importance in Jewish thought. Thanks to Google, I found this discussion in a commentary by Rabbi Aron Tendler at Torah.org:
Most of us think of Yichus from the position of the recipient not the initiator. We are the children of Avraham and Sarah, Yitzchak and Rivkah, Yakov, Rachel, and Leah. We are the recipients of their unique accomplishments and reputations. We did nothing to earn it, yet it defines who we are. Unfortunately, many of those who have it do not know that they have it, or care that they have it. That means that as important as Yichus might be to the recipients its practical value is only as great as the recipient's awareness and caring. Understanding Yichus demands that we begin seeing Yichus from the position of the initiator, the one who really cares about it, rather than the recipient who may care less.
As Moshe began his final words to the Bnai Yisroel the question of Yichus was foremost in his mind. Moshe was the product of Yichus and also the creator of his own Yichus. He knew that the amazing experiences of the 40 years in the desert were the foundation of the nation's identity and Yichus. It was what made them unique and apart from all the other nations of the world. Therefore, it needed to be preserved in the written word, but even more so, in the hearts and minds of the nation. It was incumbent upon the children of the Exodus to embrace their own Yichus so that they could be the progenitors of Yichus for their own children and grandchildren.
The transmission of Yichus is far more the responsibility of the initiator than the recipient. The initiator must engender in his recipients a sense of pride in the past and personal commitment for the present and future. The actions of the fathers are a foretelling for their children because it is the actions of the fathers that guarantee the passage of Yichus to their children.
Everyone knows that personal Yichus is the most important Yichus of all. However, every new beginning is really a reconnecting with a Yichus that extends back to the Avos, Imahos, and Moshe Rabbeinu. Personal Yichus simply picks up where previous generations left off.
Gathered in the Plains of Moab within sight of the Promised Land, Moshe summoned the entire assembly. His call was all embracing and inclusive, from the heads of the Tribes to the water-carriers and woodchoppers. He addressed a population of men, women, and children uniquely diverse and independent, yet sharing a collective Yichus and destiny. As a nation they had been molded apart from Egypt and independent of the outside world. However, they were the Sons of Jacob and they were not independent of each other.
"Each of you serves an essential job in the collective service of G-d. You cannot do it alone. You cannot give over the full Yichus without each other. We are a nation and it was to a nation that G-d gave His Torah. From the greatest to the lowest, from the most scholarly to the simplest, each of you has a job and each of you is responsible to the collective future of our people. We have all gathered to accept G-d's covenant and be His nation. So it was promised to our fore fathers and so will you witness the completion of that promise. However, far more important than being the fulfillment of past promises is your main job as guarantors of the future."