Recombination in yeast mitochondrial DNA

✍ Scribed by Shannon, Charles ;Rao, Ayyagari ;Douglass, Stephen ;Criddle, R. S.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1972
• Tongue: English
• Weight: 425 KB
• Volume: 1
• Category: Article
• ISSN: 0091-7419
• DOI: 10.1002/jss.400010207

✦ Synopsis

When h a p l o i d y e a s t s t r a i n s c o n t a i n i n g m i t o c h o n d r i a l DNAs (mtDNAs) o f d i f f e r e n t buoyant d e n s i t i e s a r e mated, t h e r e s u l t i n g zygotes c o n t a i n a mixed p o p u l a t i o n o f m i t o c h o n d r i a and m i t o c h o n d r i a l DNAs. D u r i n g v e g e t a t i v e growth o f d i p l o i d c e l l s formed f r o m such a c r o s s between a p e t i t e s t r a i n w i t h m t D N A o f d e n s i t y 1.677 g cm-3 and a r e s p i r a t o r y competent s t r a i n w i t h m t D N A o f d e n s i t y 1.684 g ~r n -~, mtDNAs w i t h i n t e r m e d i a t e buoyant d e n s i t i e s a r e o b t a i n e d .

V i r t u a ll y a l l newly s y n t h e s i z e d mtDNA i n d i p l o i d p -progeny has t h e i nt e r m e d i a t e buoyant d e n s i t y .

T h e r e f o r e , w i t h i n 2 g e n e r a t i o n s o f growth o f t h e d i p l o i d c e l l s , t h e i n t e r m e d i a t e buoyant d e n s i t y s p e c i e s predominate.

I n crosses between a r e s p i r a t o r y competent s t r a i n and o t h e r p e t i t e s t r a i n s w i t h d i f f e r e n t v a l u e s o f g e n e t i c suppres'siveness, i t was found t h a t t h e amount o f r e c o m b i n a t i o n y i e l d i n g mtDNAs o f i n t e r m e d i a t e buoyant d e n s i t i e s r o u g h l y p a r a ll e l s t h e degree o f suppressiveness.

I n d i v i d u a l c l o n e s o f r e s p i r at o r y d e f i c i e n t c e l l s f r o m such crosses were a l s o i s o l a t e d t o conf i r m t h a t s t a b l e mtDNAs w i t h i n t e r m e d i a t e buoyant d e n s i t i e s were o b t a i n e d .