The first clause is from 1 Chronicles 2.4 (“and Tamar his wife [Hebrew: daughter-in-law] gave birth to Perez and Zerah”).

Many languages have to make by Tamar a separate sentence: “Their mother was Tamar.”

In 1 Chronicles 2.9 Ram is mentioned as one of the sons of Hezron. For Ram the Septuagint has Aram (see the RSV footnote), but Ram is obviously the person who is meant, and many modern translations follow this spelling (Phillips, New English Bible, New American Bible, New Jerusalem Bible [New Jerusalem Bible], Translator’s New Testament, though others maintain the Septuagint spelling (Traduction œcuménique de la Bible, Zürcher Bibel, Barclay, Moffatt, An American Translation). The advantage of using Ram is that it avoids confusion with the several Arams mentioned in the Old Testament (see Gen 10.22, 23; 22.21; Num 23.7; 2 Sam 8.6; 15.8; 1 Chr 1.17; 2.23; 7.34; Hos 12.12; Zech 9.1), some of which are people and the others are places, but none of which are the person intended by Matthew. See the comments on names in 1.1.

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on the Gospel of Matthew. (UBS Handbook Series). New York: UBS, 1988. For this and other handbooks for translators see here .