Nissan engine lineage query

[E16T]

Hello all

Have a few questions regarding the lineage of Nissan’s engines up until recently, since have not been able to find any clear information.

Beginning with the Nissan A before progressing through with the Nissan E OHC, Nissan MA and Nissan CA (possibly the CD diesel) engines. Is it known if the later Nissan SR, GA, CG, CR and QG engines also featured the characteristic un-skirted crankcase block of the BMC A-Series or did that trace lineage end with one of the subsequent engines?

Additionally to what extent were the CG/CR, GA/QC and SR engines themselves developments of the MA, E OHC and CA engines respectively or were all of them entirely clean sheet designs by that point (as was probably the case with the MR engine too)?

Regards