Last updated: 2019-10-15

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library(tidyverse)
library(knitr)
library(matrixStats)
library(dplyr)
library(ggExtra)
library(reshape2)

Are eGenes that are shared between humans and chimps more likely to be eGenes in many tissues?

From a table of eGene qvalues across all GTEx tissues (GTEx v7 release), first get distribution of how many tissues each gene has a qval under some threshold

GTEx <- read.table("../data/AllGTExTissues.egenes.txt", header=T, sep='\t')

Threshold=0.1
TissueEgeneCount <- data.frame(TissueCount=rowSums(GTEx[,-1]<=Threshold, na.rm=T), Gene.stable.ID=gsub("\\.\\d+", "", GTEx$gene_id, perl=T))


hist(TissueEgeneCount$TissueCount, breaks=50)

Version Author Date
b62b089 Benjmain Fair 2019-08-21

From my data, plot this distribution (as a cumulative dist) after stratifying into human-specific eGenes, versus shared eGenes.

eQTLs <- read.table(gzfile("../data/PastAnalysesDataToKeep/20190521_eQTLs_250kB_10MAF.txt.gz"), header=T)
kable(head(eQTLs))
snps gene beta statistic pvalue FDR qvalue
ID.1.126459696.ACCCTAGTAAG.A ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
ID.1.126465687.TTGT.A ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
ID.1.126465750.TG.CT ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
ID.1.126465756.T.C ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
ID.1.126465766.C.A ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
ID.1.126465774.G.A ENSPTRG00000001061 3.570039 12.50828 0 3.5e-06 3.5e-06
# List of chimp tested genes
ChimpTestedGenes <- rownames(read.table('../output/ExpressionMatrix.un-normalized.txt.gz', header=T, check.names=FALSE, row.names = 1))

ChimpToHumanGeneMap <- read.table("../data/Biomart_export.Hsap.Ptro.orthologs.txt.gz", header=T, sep='\t', stringsAsFactors = F)
kable(head(ChimpToHumanGeneMap))
Gene.stable.ID Transcript.stable.ID Chimpanzee.gene.stable.ID Chimpanzee.gene.name Chimpanzee.protein.or.transcript.stable.ID Chimpanzee.homology.type X.id..target.Chimpanzee.gene.identical.to.query.gene X.id..query.gene.identical.to.target.Chimpanzee.gene dN.with.Chimpanzee dS.with.Chimpanzee Chimpanzee.orthology.confidence..0.low..1.high.
ENSG00000198888 ENST00000361390 ENSPTRG00000042641 MT-ND1 ENSPTRP00000061407 ortholog_one2one 94.6541 94.6541 0.0267 0.5455 1
ENSG00000198763 ENST00000361453 ENSPTRG00000042626 MT-ND2 ENSPTRP00000061406 ortholog_one2one 96.2536 96.2536 0.0185 0.7225 1
ENSG00000210127 ENST00000387392 ENSPTRG00000042642 MT-TA ENSPTRT00000076396 ortholog_one2one 100.0000 100.0000 NA NA NA
ENSG00000198804 ENST00000361624 ENSPTRG00000042657 MT-CO1 ENSPTRP00000061408 ortholog_one2one 98.8304 98.8304 0.0065 0.5486 1
ENSG00000198712 ENST00000361739 ENSPTRG00000042660 MT-CO2 ENSPTRP00000061402 ortholog_one2one 97.7974 97.7974 0.0106 0.5943 1
ENSG00000228253 ENST00000361851 ENSPTRG00000042653 MT-ATP8 ENSPTRP00000061400 ortholog_one2one 94.1176 94.1176 0.0325 0.3331 1
# Of this ortholog list, how many genes are one2one
table(ChimpToHumanGeneMap$Chimpanzee.homology.type)

ortholog_many2many  ortholog_one2many   ortholog_one2one 
              2278              19917             140351 
OneToOneMap <- ChimpToHumanGeneMap %>%
  filter(Chimpanzee.homology.type=="ortholog_one2one") %>%
  distinct(Chimpanzee.gene.stable.ID, .keep_all = TRUE) %>%
  left_join(TissueEgeneCount, by="Gene.stable.ID")

# Read gtex heart egene list
# Only consider those that were tested in both species and are one2one orthologs
GtexHeartEgenes <- read.table("../data/Heart_Left_Ventricle.v7.egenes.txt.gz", header=T, sep='\t', stringsAsFactors = F) %>%
  mutate(gene_id_stable = gsub(".\\d+$","",gene_id)) %>%
  filter(gene_id_stable %in% OneToOneMap$Gene.stable.ID) %>%
  mutate(chimp_id = plyr::mapvalues(gene_id_stable, OneToOneMap$Gene.stable.ID,  OneToOneMap$Chimpanzee.gene.stable.ID, warn_missing = F)) %>%
  filter(chimp_id %in% ChimpTestedGenes)

ChimpToHuman.ID <- function(Chimp.ID){
  #function to convert chimp ensembl to human ensembl gene ids
  return(
    plyr::mapvalues(Chimp.ID, OneToOneMap$Chimpanzee.gene.stable.ID, OneToOneMap$Gene.stable.ID, warn_missing = F)
  )}

HumanFDR <- 0.1
ChimpFDR <- 0.1

#Get chimp eQTLs
Chimp_eQTLs <- eQTLs %>%
  filter(qvalue<ChimpFDR)

# Count chimp eGenes
length(unique(Chimp_eQTLs$gene))
[1] 336
# Count human eGenes
length(GtexHeartEgenes %>% filter(qval< HumanFDR) %>% pull(chimp_id))
[1] 5410
# Count number genes tested in both species (already filtered for 1to1 orthologs)
length(GtexHeartEgenes$gene_id_stable)
[1] 11586
#Change FDR thresholds or take top N eGenes by qvalue
HumanTopN <- 600
HumanFDR <- 0.1
ChimpFDR <- 0.1

# Filter human eGenes by qval threshold
# HumanSigGenes <- GtexHeartEgenes %>% filter(qval<HumanFDR) %>% pull(chimp_id)

# Filter human eGenes by topN qval
HumanSigGenes <- GtexHeartEgenes %>% top_n(-HumanTopN, qval) %>% pull(chimp_id)

# Filter human eGeness by qval threshold then topN betas 
# HumanSigGenes <- GtexHeartEgenes %>% filter(qval<HumanFDR) %>% top_n(1000, abs(slope)) %>% pull(chimp_id)

HumanNonSigGenes <- GtexHeartEgenes %>%
  filter(!chimp_id %in% HumanSigGenes) %>%
  pull(chimp_id)

ChimpSigGenes <- GtexHeartEgenes %>%
  filter(chimp_id %in% Chimp_eQTLs$gene) %>%
  pull(chimp_id)

ChimpNonSigGenes <- GtexHeartEgenes %>%
  filter(! chimp_id %in% Chimp_eQTLs$gene) %>%
  pull(chimp_id)



ContigencyTable <- matrix( c( length(intersect(ChimpSigGenes,HumanSigGenes)),
                              length(intersect(HumanSigGenes,ChimpNonSigGenes)),
                              length(intersect(ChimpSigGenes,HumanNonSigGenes)),
                              length(intersect(ChimpNonSigGenes,HumanNonSigGenes))), 
                           nrow = 2)

rownames(ContigencyTable) <- c("Chimp eGene", "Not Chimp eGene")
colnames(ContigencyTable) <- c("Human eGene", "Not human eGene")

#what is qval threshold for human eGene classification in this contigency table
print(GtexHeartEgenes %>% top_n(-HumanTopN, qval) %>% top_n(1, qval) %>% pull(qval))
[1] 5.83223e-12
#Contigency table of one to one orthologs tested in both chimps and humans of whether significant in humans, or chimps, or both, or neither
ContigencyTable
                Human eGene Not human eGene
Chimp eGene              28             252
Not Chimp eGene         572           10734
#One-sided Fisher test for greater overlap than expected by chance
fisher.test(ContigencyTable, alternative="greater")

    Fisher's Exact Test for Count Data

data:  ContigencyTable
p-value = 0.0006395
alternative hypothesis: true odds ratio is greater than 1
95 percent confidence interval:
 1.444504      Inf
sample estimates:
odds ratio 
  2.084996 
#Chimp eGenes vs non chimp eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% ChimpSigGenes ~ "chimp.eGene",
        !chimp_id %in% ChimpSigGenes ~ "not.chimp.eGene")) %>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Chimp.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="greater")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Human eGenes vs non human eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% HumanSigGenes ~ "human.eGene",
        !chimp_id %in% HumanSigGenes ~ "not.human.eGene")) %>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Human.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="greater")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Shared eGenes vs human-specific eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
  filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes)))%>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Shared.human.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="less")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Shared eGenes vs chimp-specific eGenes
ToPlot <- GtexHeartEgenes %>%
  left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID")) %>%
mutate(dN.dS = dN.with.Chimpanzee/dS.with.Chimpanzee) %>%
mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(ChimpSigGenes, HumanSigGenes) ~ "chimp.specific.eGene")) %>%
dplyr::filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(ChimpSigGenes, HumanSigGenes)))
Shared.chimp.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="less")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

Chimp.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21
Human.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21
Shared.human.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21
Shared.chimp.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21

Main finding:

Shared eGenes tend to be eGenes in more GTEx tissues than human specific eGenes

Make same plots, but using top 600 human eGenes to classify heart eGene for purposes of species sharing.

#Change FDR thresholds or take top N eGenes by qvalue
HumanTopN <- 1000
HumanFDR <- 0.1
ChimpFDR <- 0.1

# Filter human eGenes by qval threshold
# HumanSigGenes <- GtexHeartEgenes %>% filter(qval<HumanFDR) %>% pull(chimp_id)

# Filter human eGenes by topN qval
HumanSigGenes <- GtexHeartEgenes %>% top_n(-HumanTopN, qval) %>% pull(chimp_id)

# Filter human eGeness by qval threshold then topN betas 
# HumanSigGenes <- GtexHeartEgenes %>% filter(qval<HumanFDR) %>% top_n(1000, abs(slope)) %>% pull(chimp_id)

HumanNonSigGenes <- GtexHeartEgenes %>%
  filter(!chimp_id %in% HumanSigGenes) %>%
  pull(chimp_id)

ChimpSigGenes <- GtexHeartEgenes %>%
  filter(chimp_id %in% Chimp_eQTLs$gene) %>%
  pull(chimp_id)

ChimpNonSigGenes <- GtexHeartEgenes %>%
  filter(! chimp_id %in% Chimp_eQTLs$gene) %>%
  pull(chimp_id)



ContigencyTable <- matrix( c( length(intersect(ChimpSigGenes,HumanSigGenes)),
                              length(intersect(HumanSigGenes,ChimpNonSigGenes)),
                              length(intersect(ChimpSigGenes,HumanNonSigGenes)),
                              length(intersect(ChimpNonSigGenes,HumanNonSigGenes))), 
                           nrow = 2)

rownames(ContigencyTable) <- c("Chimp eGene", "Not Chimp eGene")
colnames(ContigencyTable) <- c("Human eGene", "Not human eGene")

#what is qval threshold for human eGene classification in this contigency table
print(GtexHeartEgenes %>% top_n(-HumanTopN, qval) %>% top_n(1, qval) %>% pull(qval))
[1] 3.95822e-08
#Contigency table of one to one orthologs tested in both chimps and humans of whether significant in humans, or chimps, or both, or neither
ContigencyTable
                Human eGene Not human eGene
Chimp eGene              36             244
Not Chimp eGene         964           10342
#One-sided Fisher test for greater overlap than expected by chance
fisher.test(ContigencyTable, alternative="greater")

    Fisher's Exact Test for Count Data

data:  ContigencyTable
p-value = 0.01
alternative hypothesis: true odds ratio is greater than 1
95 percent confidence interval:
 1.14537     Inf
sample estimates:
odds ratio 
  1.582765 
#Chimp eGenes vs non chimp eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% ChimpSigGenes ~ "chimp.eGene",
        !chimp_id %in% ChimpSigGenes ~ "not.chimp.eGene")) %>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Chimp.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="greater")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Human eGenes vs non human eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% HumanSigGenes ~ "human.eGene",
        !chimp_id %in% HumanSigGenes ~ "not.human.eGene")) %>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Human.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="greater")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Shared eGenes vs human-specific eGenes
ToPlot <- GtexHeartEgenes %>%
  mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
  filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes)))%>%
left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID"))
Shared.human.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="less")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

#Shared eGenes vs chimp-specific eGenes
ToPlot <- GtexHeartEgenes %>%
  left_join(OneToOneMap, by=c("chimp_id"="Chimpanzee.gene.stable.ID")) %>%
mutate(dN.dS = dN.with.Chimpanzee/dS.with.Chimpanzee) %>%
mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(ChimpSigGenes, HumanSigGenes) ~ "chimp.specific.eGene")) %>%
dplyr::filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(ChimpSigGenes, HumanSigGenes)))
Shared.chimp.tissue.plot <- ggplot(ToPlot, aes(color=group,x=TissueCount)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("TissueCount") +
  annotate("text", x = 40, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, TissueCount ~ group, alternative="less")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())

Chimp.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21
Human.tissue.plot

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b62b089 Benjmain Fair 2019-08-21
Shared.human.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21
Shared.chimp.tissue.plot

Version Author Date
b62b089 Benjmain Fair 2019-08-21

Ok the same main result seems true with this much more stringent cutoff for human eGenes (which only leaves 28 shared eGenes), but could be due to chance (P=0.11). Perhaps for publication it is best to show results at these various thresholds in the supplement, to show these trends generally hold across various reasonable thresholds for classifying human eGenes.

Next I want to see if the shared eGenes are more likely to be expressed in just a few tissues or highly expressed in all tissues. I hypothesize the shared eGenes are more likely to be tissue specific, as tissue specific genes are more likely to be neutral, since deleterious genes need only be deleterious in one tissue for it to be selected against.

First I will look at expression levels (TPM) of shared eGenes vs species specific eGenes

#read in median GTEx TPM for each gene
GTEx.Expression <- read.table("../data/GTEx_Analysis_2016-01-15_v7_RNASeQCv1.1.8_gene_median_tpm.gct.gz", sep='\t', skip=2, header=T,check.names=FALSE)

GTEx.Expression[1:10,1:10] %>% kable()
gene_id Description Adipose - Subcutaneous Adipose - Visceral (Omentum) Adrenal Gland Artery - Aorta Artery - Coronary Artery - Tibial Bladder Brain - Amygdala
ENSG00000223972.4 DDX11L1 0.056945 0.05054 0.074600 0.03976 0.04386 0.04977 0.05878 0.089315
ENSG00000227232.4 WASH7P 11.850000 9.75300 8.023000 12.51000 12.30000 11.59000 14.24000 5.743000
ENSG00000243485.2 MIR1302-11 0.061460 0.05959 0.081790 0.04297 0.05848 0.05184 0.06097 0.115450
ENSG00000237613.2 FAM138A 0.038600 0.03245 0.040500 0.02815 0.03678 0.03894 0.04113 0.056265
ENSG00000268020.2 OR4G4P 0.035695 0.00000 0.034790 0.00000 0.00000 0.00000 0.00000 0.050520
ENSG00000240361.1 OR4G11P 0.042680 0.03988 0.049065 0.03399 0.00000 0.04286 0.00000 0.062955
ENSG00000186092.4 OR4F5 0.051450 0.04558 0.061360 0.00000 0.04069 0.04669 0.05461 0.097705
ENSG00000238009.2 RP11-34P13.7 0.162500 0.12020 0.087785 0.13510 0.13690 0.14720 0.14300 0.070360
ENSG00000233750.3 CICP27 0.124400 0.13470 0.148800 0.10260 0.11950 0.11450 0.07610 0.166150
ENSG00000237683.5 AL627309.1 5.992500 8.38500 6.595500 6.37800 6.06100 2.69100 4.28200 1.679500
#Get list of brain subtypes to exclude (let's just include brain cerebellum for this analysis)
#...too many brain subtypes is redundant
BrainsSubtypesToExclude<-colnames(GTEx.Expression) %>% grep("Brain", ., value=T) %>% grep("Cerebellum", ., value=T, invert=T)

GTEx.Expression.filtered <- GTEx.Expression %>%
  mutate(human_id=gsub("\\.\\d+$", "", gene_id, perl=T)) %>%
  select(-c(gene_id, BrainsSubtypesToExclude, Description)) %>%
  filter(human_id %in% GtexHeartEgenes$gene_id_stable) %>%
  mutate(Means = rowMedians(as.matrix(.[,-42]))) %>%
  mutate(chimp_id=plyr::mapvalues(human_id, OneToOneMap$Gene.stable.ID, OneToOneMap$Chimpanzee.gene.stable.ID, warn_missing = F))


ToPlot <- GTEx.Expression.filtered %>%
  mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
  filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes)))%>%
  select(human_id, group, Means, 1:41) %>%
  melt(value.name="expression")

GtexTissueColors <- read.table("../data/GTEx_Analysis_TissueColorCodes.txt", header=T, sep='\t') %>%
  rbind(data.frame(Tissue="Means", Color.code="000000"), .) %>%
  filter(Tissue %in% ToPlot$variable) %>%
  mutate(HexCode=paste0("#", Color.code))

Human.tissue.expression.plot <- ggplot(ToPlot, aes(color=group,x=variable, y=expression)) +
  geom_boxplot(outlier.shape = NA, fatten = 4) +
  scale_y_continuous(trans="log10", limits=c(0.01, 5000)) +
  ylab("expression\nlog10(TPM)") +
  # geom_point(data=GtexTissueColors, aes(y=1,x=Tissue, color=HexCode)) +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5),
        axis.ticks.x = element_line(colour = GtexTissueColors$HexCode, size = 2),
        axis.title.x=element_blank())
Human.tissue.expression.plot

Version Author Date
7810819 Benjmain Fair 2019-10-01
#Are any of the differences in those groups significant... Try muscle for example
ToCompare <- GTEx.Expression.filtered %>%
  mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
  filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes))) %>%
  select(human_id, group, Means, 1:41)
wilcox.test(data=ToCompare, `Muscle - Skeletal` ~ group, alternative="greater")

    Wilcoxon rank sum test with continuity correction

data:  Muscle - Skeletal by group
W = 19718, p-value = 0.08218
alternative hypothesis: true location shift is greater than 0

Ok so the shared eGenes seem to be slightly lower expressed in all tissues, though it could be just chance.

Ok now I will look at tissue specificity on a per-tissue level (are the shared eGenes specific for any particular tissue?). First I will do this by looking at Z-scores of expression (for each gene, standardize the measurements across tissues into Z-score).

ToPlot <- GTEx.Expression.filtered %>%
  select(1:41) %>% as.matrix() %>% log10() %>% t() %>% scale() %>% t() %>% as.data.frame() %>%
  mutate(human_id=GTEx.Expression.filtered$human_id, chimp_id=GTEx.Expression.filtered$chimp_id) %>%
    mutate(group = case_when(
        # chimp_id %in% HumanSigGenes ~ "human.eGene",
        # !chimp_id %in% HumanSigGenes ~ "not.human.eGene")) %>%
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
  filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes)))%>%
  melt(value.name="expression")

GtexTissueColors <- read.table("../data/GTEx_Analysis_TissueColorCodes.txt", header=T, sep='\t') %>%
  # rbind(data.frame(Tissue="Means", Color.code="000000"), .) %>%
  filter(Tissue %in% ToPlot$variable) %>%
  mutate(HexCode=paste0("#", Color.code))

Human.tissue.expression.Z.plot <- ggplot(ToPlot, aes(color=group,x=variable, y=expression)) +
  geom_boxplot(outlier.shape = NA, fatten = 4) +
  ylab("expression\nZ-score") +
  # geom_point(data=GtexTissueColors, aes(y=1,x=Tissue, color=HexCode)) +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5),
        axis.ticks.x = element_line(colour = GtexTissueColors$HexCode, size = 2),
        axis.title.x=element_blank())
Human.tissue.expression.Z.plot

Version Author Date
7810819 Benjmain Fair 2019-10-01

Now look at tissue specificity, as calculated with gini and tau statistics from the GTEx tissue data. Using both slightly different statistics to make sure the general finding is robust to choice of statistic

tau<-read.table("../output/TissueSpecificity/tau.log.txt", col.names =c('gene', 'tau'), sep='\t')
gini<-read.table("../output/TissueSpecificity/gini.log.txt", col.names =c('gene', 'gini'), sep='\t')
tissue.specificity <- merge(tau, gini) %>%
  filter(gene %in% GtexHeartEgenes$gene_id_stable) %>%
  mutate(chimp_id=plyr::mapvalues(gene, OneToOneMap$Gene.stable.ID, OneToOneMap$Chimpanzee.gene.stable.ID, warn_missing = F))
  

p<- ggplot(tissue.specificity, aes(x=gini, y=tau)) +
  geom_point(alpha=0.05) +
  theme_bw()

#scatter plot and histograms of tau and gini over all tested genes
tauVgini <- ggExtra::ggMarginal(p, type = "histogram")
library(grid)
grid.newpage()
grid.draw(tauVgini)

Version Author Date
7810819 Benjmain Fair 2019-10-01
ToPlot <- tissue.specificity %>%
  mutate(group = case_when(
        chimp_id %in% intersect(HumanSigGenes, ChimpSigGenes) ~ "shared.eGene",
        chimp_id %in% setdiff(HumanSigGenes, ChimpSigGenes) ~ "human.specific.eGene")) %>%
        filter(chimp_id %in% union(intersect(HumanSigGenes, ChimpSigGenes), setdiff(HumanSigGenes, ChimpSigGenes)))
        # chimp_id %in% HumanSigGenes ~ "chimp.eGene",
        # !chimp_id %in% HumanSigGenes ~ "not.chimp.eGene"))

Human.tissue.specificity.plot <- ggplot(ToPlot, aes(color=group,x=tau)) +
  stat_ecdf(geom = "step") +
  ylab("Cumulative frequency") +
  xlab("Tissue specificity (tau)") +
  annotate("text", x = 0.4, y = 0.4, label = paste("Mann-Whitney\none-sided P =", signif(wilcox.test(data=ToPlot, tau ~ group, alternative="less")$p.value, 2) )) +
  theme_bw() +
  theme(legend.position = c(.80, .2), legend.title=element_blank())
Human.tissue.specificity.plot

Version Author Date
7810819 Benjmain Fair 2019-10-01

sessionInfo()
R version 3.5.1 (2018-07-02)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS  10.14

Matrix products: default
BLAS: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRblas.0.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
 [1] reshape2_1.4.3     ggExtra_0.9        matrixStats_0.54.0
 [4] knitr_1.23         forcats_0.4.0      stringr_1.4.0     
 [7] dplyr_0.8.1        purrr_0.3.2        readr_1.3.1       
[10] tidyr_0.8.3        tibble_2.1.3       ggplot2_3.1.1     
[13] tidyverse_1.2.1   

loaded via a namespace (and not attached):
 [1] tidyselect_0.2.5 xfun_0.7         haven_2.1.0      lattice_0.20-38 
 [5] colorspace_1.4-1 generics_0.0.2   miniUI_0.1.1.1   htmltools_0.3.6 
 [9] yaml_2.2.0       rlang_0.3.4      later_0.8.0      pillar_1.4.1    
[13] glue_1.3.1       withr_2.1.2      modelr_0.1.4     readxl_1.3.1    
[17] plyr_1.8.4       munsell_0.5.0    gtable_0.3.0     workflowr_1.4.0 
[21] cellranger_1.1.0 rvest_0.3.4      evaluate_0.14    labeling_0.3    
[25] httpuv_1.5.1     highr_0.8        broom_0.5.2      Rcpp_1.0.1      
[29] xtable_1.8-4     promises_1.0.1   scales_1.0.0     backports_1.1.4 
[33] jsonlite_1.6     mime_0.7         fs_1.3.1         hms_0.4.2       
[37] digest_0.6.19    stringi_1.4.3    shiny_1.3.2      rprojroot_1.3-2 
[41] cli_1.1.0        tools_3.5.1      magrittr_1.5     lazyeval_0.2.2  
[45] crayon_1.3.4     whisker_0.3-2    pkgconfig_2.0.2  xml2_1.2.0      
[49] lubridate_1.7.4  assertthat_0.2.1 rmarkdown_1.13   httr_1.4.0      
[53] rstudioapi_0.10  R6_2.4.0         nlme_3.1-140     git2r_0.25.2    
[57] compiler_3.5.1