Limits...
Selection for replicases in protocells.

Bianconi G, Zhao K, Chen IA, Nowak MA - PLoS Comput. Biol. (2013)

Bottom Line: In a well-mixed medium, natural selection would not favor such replicases because their presence equally benefits sequences with or without replicase activity.Here we show that protocells can select for replicases.We calculate the error threshold that is compatible with selecting for replicases.

View Article: PubMed Central - PubMed

Affiliation: School of Mathematical Sciences, Queen Mary University of London, London, United Kingdom.

ABSTRACT
We consider a world of nucleotide sequences and protocells. The sequences have the property of spontaneous self-replication. Some sequences - so-called replicases - have enzymatic activity in the sense of enhancing the replication rate of all (or almost all) sequences. In a well-mixed medium, natural selection would not favor such replicases because their presence equally benefits sequences with or without replicase activity. Here we show that protocells can select for replicases. We assume that sequences replicate within protocells and that protocells undergo spontaneous division. This leads to particular population structures which can augment the abundance of replicases. We explore various assumptions regarding replicase activity and protocell division. We calculate the error threshold that is compatible with selecting for replicases.

Show MeSH
Division mechanism.When a protocell reaches the maximum size , it splits. Here we consider two splitting mechanisms. In the first case the protocell splits into two daughter protocells, of random composition, with each protocell containing at least one sequence. In the second case, the protocell splits into  daughter protocells, and each daughter protocell contains a sequence.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3649988&req=5

pcbi-1003051-g003: Division mechanism.When a protocell reaches the maximum size , it splits. Here we consider two splitting mechanisms. In the first case the protocell splits into two daughter protocells, of random composition, with each protocell containing at least one sequence. In the second case, the protocell splits into daughter protocells, and each daughter protocell contains a sequence.

Mentions: Replication within a protocell increases the number of sequences inside the protocell. We assume that the cell divides once a certain maximum number, , of sequences has been reached. We consider two types of cell division. (i) Division into two: each sequence of the parent cell is given at random to one of the two daughter cells. (ii) Division into many: each daughter cell contains exactly one sequence. In both cases we do not need to keep track of empty cells. In Figure 3 we show how the different mechanisms for cell division work for a protocell of maximal size .


Selection for replicases in protocells.

Bianconi G, Zhao K, Chen IA, Nowak MA - PLoS Comput. Biol. (2013)

Division mechanism.When a protocell reaches the maximum size , it splits. Here we consider two splitting mechanisms. In the first case the protocell splits into two daughter protocells, of random composition, with each protocell containing at least one sequence. In the second case, the protocell splits into  daughter protocells, and each daughter protocell contains a sequence.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3649988&req=5

pcbi-1003051-g003: Division mechanism.When a protocell reaches the maximum size , it splits. Here we consider two splitting mechanisms. In the first case the protocell splits into two daughter protocells, of random composition, with each protocell containing at least one sequence. In the second case, the protocell splits into daughter protocells, and each daughter protocell contains a sequence.
Mentions: Replication within a protocell increases the number of sequences inside the protocell. We assume that the cell divides once a certain maximum number, , of sequences has been reached. We consider two types of cell division. (i) Division into two: each sequence of the parent cell is given at random to one of the two daughter cells. (ii) Division into many: each daughter cell contains exactly one sequence. In both cases we do not need to keep track of empty cells. In Figure 3 we show how the different mechanisms for cell division work for a protocell of maximal size .

Bottom Line: In a well-mixed medium, natural selection would not favor such replicases because their presence equally benefits sequences with or without replicase activity.Here we show that protocells can select for replicases.We calculate the error threshold that is compatible with selecting for replicases.

View Article: PubMed Central - PubMed

Affiliation: School of Mathematical Sciences, Queen Mary University of London, London, United Kingdom.

ABSTRACT
We consider a world of nucleotide sequences and protocells. The sequences have the property of spontaneous self-replication. Some sequences - so-called replicases - have enzymatic activity in the sense of enhancing the replication rate of all (or almost all) sequences. In a well-mixed medium, natural selection would not favor such replicases because their presence equally benefits sequences with or without replicase activity. Here we show that protocells can select for replicases. We assume that sequences replicate within protocells and that protocells undergo spontaneous division. This leads to particular population structures which can augment the abundance of replicases. We explore various assumptions regarding replicase activity and protocell division. We calculate the error threshold that is compatible with selecting for replicases.

Show MeSH