206
M.Akam
5 Conclusions
At present the Hox genes provide one of the best examples where patterns of gene
expression can be related to the diversity of form. I have considered only studies on
arthropods, but analogous studies on vertebrates are already providing an understanding of form and diversity among the vertebrates (e.g. Burke et a1. 1995; Cohn
et a1. 1997). Relating these molecular studies to the fossil record promises a fascinating synthesis.
The Hox genes are not unique. They are but one among many groups of genes
that can provide insight into the origins of diversity. Other families of genes are
involved in generating the diversity of tissue types and, within anyone tissue, the
diversity of behaviour and function exhibited by specialised cells among, for example, the nerves and muscles. Developmental genetics, coupled with comparative
genomics, will provide a new and richer understanding of this diversity, as it arises
both in ontogeny and phylogeny.
Acknowledgements
Work in the author's laboratory was supported by the Wellcome Trust and the
Biotechnology and Biological Science Research Council of the United Kingdom.
References
Abouheif E, Akam M, Dickinson WJ, Holland PWH, Meyer A, Patel NH, Raff RA, Roth
VL, Wray GA (1997) Homology and developmental genes. Trends Genet 13:432-433
Affolter M, Schier A, Gehring WJ (1990) Homeodomain proteins and the regulation of gene
expression. Current Opinion Cell BioI 2:485-495
Aguinaldo AMA, Turbeville JM, Linford LS, Rivera MC, Garey JR, Raff RA, Lake JA
(1997) Evidence for a clade of nematodes arthropods and other moulting animals. Nature 387:489-493
Akam M (1987) The molecular basis for metameric pattern in the Drosophila embryo. Development 101:1-22
Akam M (1989) llox and HOM: Homologous gene clusters in insects and vertebrates. Cell
57:347-349
Arenas-Mena C, Martinez C, Cameron RA, Davidson EH (1998) Expression of the Hox
gene complex in the indire<;:t development of a sea urchin. Proc Nat! Acad Sci USA
95:13062-13067
AverofM, Akam M (1995a) Hox genes and the diversification of insect and crustacean body
plans. Nature 376:420-423
Averof M, Akam M (1995b) Insect-crustacean relationships: insights from comparative developmental and molecular studies. Phil Trans Roy Soc 347:293-303
Averof M, Patel NH (1997) Crustacean appendage evolution associated with changes in
Hox gene expression. Nature 388:682-686
M.Akam
5 Conclusions
At present the Hox genes provide one of the best examples where patterns of gene
expression can be related to the diversity of form. I have considered only studies on
arthropods, but analogous studies on vertebrates are already providing an understanding of form and diversity among the vertebrates (e.g. Burke et a1. 1995; Cohn
et a1. 1997). Relating these molecular studies to the fossil record promises a fascinating synthesis.
The Hox genes are not unique. They are but one among many groups of genes
that can provide insight into the origins of diversity. Other families of genes are
involved in generating the diversity of tissue types and, within anyone tissue, the
diversity of behaviour and function exhibited by specialised cells among, for example, the nerves and muscles. Developmental genetics, coupled with comparative
genomics, will provide a new and richer understanding of this diversity, as it arises
both in ontogeny and phylogeny.
Acknowledgements
Work in the author's laboratory was supported by the Wellcome Trust and the
Biotechnology and Biological Science Research Council of the United Kingdom.
References
Abouheif E, Akam M, Dickinson WJ, Holland PWH, Meyer A, Patel NH, Raff RA, Roth
VL, Wray GA (1997) Homology and developmental genes. Trends Genet 13:432-433
Affolter M, Schier A, Gehring WJ (1990) Homeodomain proteins and the regulation of gene
expression. Current Opinion Cell BioI 2:485-495
Aguinaldo AMA, Turbeville JM, Linford LS, Rivera MC, Garey JR, Raff RA, Lake JA
(1997) Evidence for a clade of nematodes arthropods and other moulting animals. Nature 387:489-493
Akam M (1987) The molecular basis for metameric pattern in the Drosophila embryo. Development 101:1-22
Akam M (1989) llox and HOM: Homologous gene clusters in insects and vertebrates. Cell
57:347-349
Arenas-Mena C, Martinez C, Cameron RA, Davidson EH (1998) Expression of the Hox
gene complex in the indire<;:t development of a sea urchin. Proc Nat! Acad Sci USA
95:13062-13067
AverofM, Akam M (1995a) Hox genes and the diversification of insect and crustacean body
plans. Nature 376:420-423
Averof M, Akam M (1995b) Insect-crustacean relationships: insights from comparative developmental and molecular studies. Phil Trans Roy Soc 347:293-303
Averof M, Patel NH (1997) Crustacean appendage evolution associated with changes in
Hox gene expression. Nature 388:682-686