In this chapter, Jacob and his children move to Egypt and Joseph meets his father again.
This chapter starts with an interesting note, that God is essentially confirming that Jacob should go down to Egypt. This shows that Joseph was most likely correct, that God did send him ahead as a deliverance for his family (not to mention all of the other people who survived through the famine due to his preparations). Probably the more significant point, though, is that Jacob actually needs permission to leave the promised land. As we've seen, the patriarchs sometimes seek to leave the promised land to seek refuge during famines, but as we saw in Genesis 26, God really wanted them to stay in the land.
Dwelling in the promised land was incredibly important both to the patriarchs and to their later descendants (like the author of Genesis). It's kinda hard to explain why, but what it comes down to is that this is the land they were given as an inheritance. To leave the land is a physical action that almost seems to say, I am abandoning the promise, because it was a land given for them to dwell in.
So God giving them permission to leave is very important, especially since after this departure, Jacob and his sons will be away from the promised land for approximately 400 years, and not the brief 5-20 year periods that his forefathers left it during the famines of their time. In this respect going down to Egypt is significant, and one starts to see the massive significance of the return from Egypt, which is the topic of the next book.
The next part of the chapter is a fairly lengthy genealogy, for which I should probably coin the term YAG (Yet Another Genealogy). This genealogy is somewhat controversial as to whether it properly includes 70 people or 75, with different OT manuscripts reaching different totals. 70 would be a symbolic number of completion (7 is a full week and signifies fullness, 10 is also a number signifying completion) and that is what we find in the Masoretic Texts (the "Hebrew OT"). The Septuagint (Greek OT) and Acts 7:14 both list 75 as the total number of people. I don't know offhand what is the origin of this discrepancy, but from a theological point of view it is unimportant, it's just one of those things scholars debate.
Otherwise, this genealogy's placement here, like much of this chapter, is to commemorate the Israelite communal migration to Egypt. Genealogies like this, which center around the descendants of Jacob and the twelve tribal leaders, would serve to connect the Israelite readers with their past, since most (if not all) Israelites would know what tribe they were from and whose descendant they were. Just like prior genealogies (e.g. Genesis 10) served to place the whole nation of Israel in the larger context of the nations of the earth, this genealogy serves to place the tribes and clans of Israel in the larger context of the whole nation, in the specific context of the descent to Egypt. In this sense, I like to view genealogies as the author attempting to bring a context to the passage as the list of names and relationships give the reader a view of how these different stories fit together into a bigger picture.
In the light of this, it is particularly interesting that we get to see so many of the patriarch's mistakes. We get to see Abraham struggle with his faith, we see his mistake with Hagar, we see Jacob's various struggles and mistakes, we see the egregious errors of Reuben, Simeon and Levi. And perhaps most importantly, we see the massive errors made by Judah as well, in chapter 38. This is particularly relevant because later in Israel's history, nearly all of the living Israelites and readers of this book would be descendants of Judah (for reasons we will see later). Many nations have founding myths, like the stories about George Washington for the US, or the story of Romulus and Remus for the ancient Romans. Yet very few of these myths are willing to paint their founders in a negative light for all of the reasons I have pointed out above. The primary purpose of such myths is to give the people reading it a sense of place, of foundedness in the universe. It is a natural human tendency to want this place, this foundation, to be solely positive. That the bible contains so many negative portrayals of the Jewish fathers gives it a much greater realism and humanity in my mind.
We can also see from the number in the genealogy (70 or 75) that Jacob's children are multiplying rapidly, expanding far beyond the mere handful of his predecessors (ignoring Abraham's concubine children). As I discussed in the last chapter, the Abrahamic promise is now being diffused over the whole community rather than a single individual.
The chapter ends with the cheery reunion between Jacob and Joseph, after being separated for possibly 25-50 years. This part ends on an amusing note, as Joseph coaches his family to tell Pharaoh "We are shepherds". This appears to be a deliberate strategy to be assigned to Goshen. Joseph restates what we have seen before, that the Egyptians hate shepherds (for all of the reasons I have said before), and what we can infer from this is that Goshen is both distant from the major Egyptian cities of the time and also a very fertile land for raising livestock. Joseph calls it the "best of the land", but the reason they are sent to Goshen is to avoid disturbing the large agrarian population.