Times Book Of Crosswords

[barnaclebill58]

I would be grateful for the parsing of the following .
Begin to lose one's temper . Ans Lead off . I thought it must be that when a metal is tempered, it is covered in lead and in the course of time that lead peels off -but extensive googling gives no support for that
Hereditary factor makes major contribution here, usually. Ans In general. I get the gene bit but can't see where in and al come from.
Thanks

[Mamyalynne]

Gene is making a major contribution to the phrase 'In general'

[JJ109]

I can't parse the "L"

Hereditary factor makes major contribution here = In genera (plural of genus) + L ?? = in general (usually)

[Lie-in King]

Lead off - looks like a double definition, ref for the 2nd here -

https://tinyurl.com/8sp3st4t