This article https://gatk.broadinstitute.org/hc/en-us/articles/360035535932-Germline-short-variant-discovery-SNPs-Indels- says i should use HaplotypeCaller in GVCF mode and GenotypeGVCFs then, and this article https://gatk.broadinstitute.org/hc/en-us/articles/360035531192-RNAseq-short-variant-discovery-SNPs-Indels- advises to use HaplotypeCaller without GenotypeGVCFs. I tried the former (with one sample), and the result is similar to the result of HaplotypeCaller in non-GVCF mode, however it differs in some entries.
What is the difference between these two ways and in which cases should i use one or another? And what GenotypeGVCFs does at all? The manual page says "joint genotyping" but i have no idea what it means.
Thanks in advance.