Genomics II 23 - PDF

12 Genomics II 23 Thursday, 4 January 2024 12 Genomics… 11:40 Allopatric and sympatric sp Speciation normally allopat Parapatry describes in-bet Allopatry being completely Two units and ranges are taxonomic units. - parapa Is this the main so - Speciation w Speciation sometimes do pec...

12 Genomics II 23 Thursday, 4 January 2024 12 Genomics… 11:40 Allopatric and sympatric sp Speciation normally allopat Parapatry describes in-bet Allopatry being completely Two units and ranges are taxonomic units. - parapa Is this the main so - Speciation w Speciation sometimes do peciation tric as it requires space and some degree of spatial isolation tween allopatry and sympatry y apart and sympatry being together e slightly overlapping - some sort of gene flow between two atry ort of speciation with gene flow oesn’t always just produce two species its more dynamic than this - Speciation w Speciation sometimes do Model of stages of div Speciation may still oc Getting from two geno gene flow 1. 2. 3. 4. Two populatio But in one ran Due to differe Leads to diver and around th 5. Then genome gene flow bec 6. Ultimately pro with gene flow oesn’t always just produce two species its more dynamic than this vergence in speciation with gene flow ccur with large contact omes that are the same to two genomes that are different even with ons exchanging genes nge there is selection on one part of the genome ences in environment etc - starts pulling genomes apart rgence hitchhiking - this gene pulls along other genes with them, in his peak e hitchhiking - populations forming become sufficiently different so comes limited oduces genome level isolation leading to true species 3. Due to differe 4. Leads to diver and around th 5. Then genome gene flow bec 6. Ultimately pro There are patterns yo E.g., thes areas Associate Beginnin ences in environment etc - starts pulling genomes apart rgence hitchhiking - this gene pulls along other genes with them, in his peak e hitchhiking - populations forming become sufficiently different so comes limited oduces genome level isolation leading to true species ou see that seems like this process se two butterfly species are genomically the same apart from two ed in different with colour patterns ngs to two taxa drawing apart Another example is crow England = black crow Scotland = hooded crow Europe = other crow These two species form between these two spe In the area of diverge feather colour and a Developing sympatric Leading to two benth ws in Europe, with two sub species. m hybrid zone, and there is very little differences in genomes ecies ence in the genome, the genes are responsible for controlling also mate choice for feather colour c speciation, many crater lakes in Africa hic and limnetic Developing sympatric Leading to two benth Clusters of speciation i c speciation, many crater lakes in Africa hic and limnetic islands - linked genes that are differentiating away to form sepecies See differenti FST comparison a See as you get furth have this spike in th Suggesting deve iation across genome in species of heliconus butterflies against top butterfly for each 3 butterflies below her away in phylogeny the background FST levels increase, but all 3 he middle elopment of divergence across genome Suggesting deve Have to be careful with occurring E.g,, using only FST its o Is hard to interpret May come about due to Dip in diversity exam elopment of divergence across genome these ideas, as statistics are hard to determine as so many things only a relative measure o reduced diversity as FST measurers only relative divergence mple due to selection Dip in diversity exam Can get selection for gene Reduction in variatio Pretend they are both mutation for each mple due to selection es causing same phenotype in different populations on in both population, which can look like increased divergence h mutation to make butterflies red ( not green ) slightly different Pretend they are both mutation for each If sweep occurs t can seem like a l Real example of this c Spikes of divergen But when looking seem like there is h mutation to make butterflies red ( not green ) slightly different that is at same locus between the two - reduces diversity and hence large divergence comparing fly catchers genomes nce ( called islands of speciation ) was seen at other indicators, this is due to reduction of diversity making it divergence between two species Recombination makes Can get spikes of diverg In limited recombinatio Genome comparisons in What looks like diverge similar results gence, due to genes being in areas of limited recombination on areas you don’t get creation of differences in genomes as much n sunflowers ence, is just areas of low recombination Genome comparisons in What looks like diverge Low recombina Species are less clear t of species n sunflowers ence, is just areas of low recombination ation is a confounding affect than we think, as there is a lot of gene flow between what we think Different specie Different wing c But in a lot of ci between specie es of heliconus coloiur patterns ircumstances, different species undergo gene flow, and genes move es Looking at gene flo ABBA/BABA techni This test Shows us hybridisa And this If strong e as melop hence pe Unsure on this ow between heliconus butterfly species ique tells us if there is gene flow going on between species s here that timareta has picked up genes from melpomene by ation is common - e.g., human and Neanderthals hybridisation etc etc enough selection, the hybridfs can survive. E.g., timerata isn't as fit pomene, and the hybrids are more successful than timerata and ersist. E.g., also Generally hybrids are less fit and o coyotes and wolves have gene flow even though they are millions of years diverged d are not selected for but sometimes are