Summary
Highlights
Gregor Mendel's discoveries in 1866 laid the groundwork for genetics, establishing the Laws of Inheritance: Independent Assortment, Segregation, and Dominance. These laws explained his Theory of Particulate Inheritance, where 'discrete particles' (genes) pass phenotypic traits across generations, forming the basis of genetics and evolution.
Genetics confirms Darwin's morphological classification, placing humans within the animal kingdom and suggesting close relationships with other animals. The field of biological anthropology uses genetics to investigate human evolution and our connections to other living species, particularly primates.
The heritability of genes allows for determining evolutionary relatedness. Organisms share DNA and RNA, and the more similar two whole genomes are, the more closely related the individuals. This principle is used in paternity tests and, more broadly, to construct phylogenetic trees between different species.
The sequencing of the human (2002) and chimpanzee (2005) genomes enabled direct comparison, revealing a 98.8% identity in alignable regions and 96% identity with insertions/deletions. This high similarity indicates a closer relationship between humans and chimpanzees than between rats and mice.
Further genomic sequencing shows humans and chimpanzees are more closely related to each other than to gorillas (98% similarity) or orangutans (97% similarity), all of whom are Great Apes (Hominids). Gibbons show 96% similarity and Rhesus macaques 93%, progressively distant relatives, corroborating morphological classifications.
DNA samples from extinct relatives like Homo neanderthalensis and Denisovans reveal an even closer genetic relationship to modern humans (99.7% alignable regions) than to chimpanzees. This confirms the notion that humans are primates and apes, supporting evolutionary predictions of shared ancestry and transitional forms in the fossil record.