Herbert Macgregor (1933–2018)
Herbert was introduced to LBCs by H. G. “Mick” Callan in 1958. At that time, Herbert was a final year Honors student in the Zoology Department at St. Andrews University, Scotland, where Callan was Professor. Callan suggested that Herbert treat LBCs with various enzymes to determine whether the patterns of digestion would reveal anything about the molecular organization of the chromosomes. Pepsin, trypsin, and RNase caused generalized digestion of the chromosomes, but nothing very exciting. However, DNase was different. It caused clean “breaks” in the lateral loops and along the main axis of the chromosomes, with little or no overall loss of mass. The simplest interpretation was immediately obvious: DNA extended as a continuous backbone from one end of the chromosome to the other. Losing no time, Callan and Macgregor prepared a short note for Nature, which was published a mere 6 weeks later. Students today are taught, well before University, that chromosomes are basically long strands of DNA. It is difficult now to appreciate how revolutionary that idea was in 1958.
From this auspicious beginning, Herbert went on to establish himself as a leader in the field of chromosome research and a major spokesperson for LBCs. His formal academic career is quite straightforward. He remained at St. Andrews and completed his Ph.D. with Callan, after which he became Lecturer, a position he held until 1970. He then obtained an appointment as Professor of Zoology and Head of the Department of Zoology at the University of Leicester, England. He remained at Leicester until his retirement in 1996, when he moved to Topsham near Exeter. There he was Visiting Professor at the School of Biosciences of the University of Exeter.
Even before moving to Leicester, Herbert was one of a handful of investigators who more or less simultaneously rediscovered amplification of the genes coding for ribosomal RNA (rRNA). I say “rediscovered” because the phenomenon had, in fact, been accurately described many years earlier, but for all practical purposes had been forgotten. The details of gene amplification are too extensive to describe here, but in short, the ribosomal genes (rDNA) somehow get out of the chromosomes during early meiosis and replicate independently inside the oocyte nucleus. As a result, most of the DNA in the oocyte nucleus is actually rDNA, a small fraction of which is associated with each of the 1000 or so extrachromosomal nucleoli. During an enjoyable sabbatical that I spent in St. Andrews in 1968, Herbert and I reinvestigated one of the classical accounts of rDNA amplification, which takes place in oocytes of the giant water beetle Dytiscus.
If one were to characterize the essence of Herbert’s original research at Leicester, it would be that he used giant chromosomes from a variety of organisms—frogs, salamanders, birds, and insects—to study a wide range of phenomena. Included were gene amplification, the nature and chromosomal distribution of highly repetitive sequences, as well as the organization of telomeres and centromeres. Space does not permit a description here of each of his contributions to these aspects of chromosome structure. But throughout, he never lost interest in the LBCs and their remarkable loops. Time and again he came back to these chromosomes and to the still poorly understood relationship between their structure and the massive synthesis of RNA during oogenesis. His last two formal publications in 2012 are entitled “So what’s so special about these things called lampbrush chromosomes?” and “Chromomeres revisited.” Both were published in Chromosome Research, the journal he conceived and founded in 1992 and then edited for 20 years. From its inception, Chromosome Research has provided an important addition to the relatively few journals devoted specifically to chromosomes. It remains a forum for wide-ranging contributions on all aspects of chromosome structure and function, especially important now when studies of chromatin are so often couched in purely molecular terms.
In addition to his research and teaching, Herbert found time to write two very useful books: Macgregor HC and Varley JM (1983) Working with Animal Chromosomes, John Wiley and Sons; and Macgregor HC (1993) An Introduction to Animal Cytogenetics, Chapman and Hall.
Well known to all who work on LBCs, but perhaps not to those outside this sub-specialty, is the website “Lampbrush Chromosomes” (http://projects.exeter.ac.uk/lampbrush/), which Herbert founded and maintained. Here, one can find short biographies of nearly all “lampbrushologists” as well as an exhaustive bibliography of papers published on LBCs since the original description by Flemming in 1882.
Herbert Macgregor will be remembered for his many contributions to chromosome research as investigator, mentor, author, editor, and above all as enthusiastic cheerleader for his beloved lampbrush chromosomes.
For more information on the influence and life of Herbert Macgregor, please see the link below to Dr. Pat Heslop-Harrison’s website which contains his personal tribute to Herbert: https://molcyt.org/2018/08/13/herbert-macgregor-1933-2018-a-personal-tribute/
Herbert C. Macgregor Publications (1958 to 2012)
Callan, H.G. and H.C. Macgregor (1958). Action of deoxyribonuclease on lampbrush chromosomes. Nature, 181: 1479-1480.
Macgregor, H.C. (1962). The behaviour of isolated nuclei. Exp. Cell Res., 26: 520-525.
Macgregor, H.C. and H.G. Callan (1962). The actions of enzymes on lampbrush chromosomes. Quart. J. Microsc. Sci., 103: 172-203.
Macgregor, H.C. (1963). Morphological variability and its physiological origin in oocyte nuclei of the crested newt. Quart. J. Microsc. Sci., 104: 351-368.
Macgregor, H.C. and T.M. Uzzell (1964). Gynogenesis in salamanders related to Ambystoma jeffersonianum. Science, 143: 1043-1045.
Macgregor, H.C. and P.A. Thomasson (1965). The fine structure of two archigregarines, Selenidium fallax and Ditrypanocystis cirratuli. J. Protozool. 12: 438-443.
Macgregor, H.C. (1965). The role of lampbrush chromosomes in the formation of nucleoli in amphibian oocytes. Quart. J. Microsc. Sci., 106: 215-228.
Macgregor, H.C. (1965). The effects of mammalian gonadotrophins on the yolky oocytes of crested newts. Arch. Anat. Micr. 54: 652-653.
Macgregor, H.C. (1967). Pattern of incorporation of 3H uridine into RNA of amphibian oocyte nucleoli. J. Cell. Sci. 2: 145-150.
Macgregor, H.C. and J.B. Mackie (1967). The fine structure of the cytoplasm in salivary glands of Simulium. J. Cell. Sci. 2: 137-144.
Perkowska, E., H.C. Macgregor and M.L. Birnstiel (1968). Gene amplification in the oocyte nucleus of mutant and wild type Xenopus laevis. Nature, 217: 649-650.
Walker, M. and H.C. Macgregor (1968). Spermatogenesis and the structure of the mature sperm in Nucella lapillus (L). J. Cell. Sci. 3: 95-104.
Macgregor, H.C., (1968). Nucleolar DNA in oocytes of Xenopus laevis. J. Cell Sci., 3: 437-444.
Gall, J.G., H.C. Macgregor, and M.E. Kidston (1969). Gene amplification in the oocytes of dytiscid water beetles. Chromosoma, 26:169-187.
Riemann, W., C. Muir, and H.C. Macgregor (1969). Sodium and potassium in oocytes of Triturus cristatus. J.Cell Sci., 4: p. 299-304.
Macgregor, H.C. (1969). Observations on the role of the germinal vesicle in amphibian and insect oogenesis. Heredity, 24: p. abstract in Proceedings of the 159th meeting of the Genetical Soc. of G.B.
Macgregor, H.C. and J. Kezer (1970). Gene amplification in oocytes with 8 germinal vesicles from the tailed frog Ascaphus truei Stejneger. Chromosoma, 29: 189-206.
Macgregor, H.C. and H. Stebbings (1970). A massive system of microtubules associated with cytoplasmic movement in telotrophic ovarioles. J. Cell Sci., 6: 431-449.
Macgregor, H.C. and S.J. Moon (1971). Some measurements on amphibian oocyte nucleoli. Z. Zellforsch., 122: 273-282.
Kezer, J. and H.C. Macgregor (1971). A fresh look at meiosis and centromeric heterochromatin in the red-backed salamander Plethodon c. cinereus (Green). Chromosoma, 33: 146-166.
Macgregor, H.C. and J. Kezer (1971). The chromosomal localisation of a heavy satellite DNA in the testis of Plethodon c. cinereus . Chromosoma, 33: 167-182.
Kezer, J., H.C. Macgregor, and E. Schabtach (1971). Observations on the membranous components of amphibian oocyte nucleoli. J. Cell Sci. 8: 1-17.
Macgregor, H.C. and M. Vlad (1972). Interlocking and knotting of ring nucleoli in amphibian oocytes. Chromosoma, 39: 205-214.
Macgregor, H.C. (1972). The nucleolus and its genes in amphibian oogenesis. Biol.Rev. 47: 177-210.
Macgregor, H.C. (1973). Amplification, polytenisation and nucleolus organisers. Nature New Biology, 246: 81-82.
Macgregor, H.C., H.A. Horner, C.A. Owen and I. Parker (1973). Observations on centromeric heterochromatin and satellite DNA in salamanders of the genus Plethodon. Chromosoma, 43: 329-348.
Macgregor, H.C. and M. Walker (1973). The arrangement of chromosomes in nuclei of sperm from plethodontid salamanders. Chromosoma, 40: 243-262.
Macgregor, H.C. and J. Kezer (1973). The nucleolar organiser of Plethodon c. cinereus. I. Location of the organiser by in-situ nucleic acid hybridisation. Chromosoma, 42: 415-426.
Kezer, J. and H.C. Macgregor (1973). The nucleolar organiser of Plethodon c. cinereus. II. The lampbrush nucleolar organizer. Chromosoma, 42: 427-444.
Walker, M.H. and H.C. Macgregor (1974). The arrangement of chromosomes in elongate sperm heads. in “Chromosomes Today”, 5: 13 - 22. (John Wiley & Sons).
Mizuno, S. and H.C. Macgregor (1974). Chromosomes, and sequences and evolution in salamanders of the genus Plethodon. Chromosoma, 48: p. 239-296.
Macgregor, H.C., S. Mizuno, and M. Vlad (1974). Some recent studies on chromosomes and DNA sequences in salamanders. in “Chromosomes Today” 5: 331 - 339. (John Wiley & Sons).
Vlad, M. and H.C. Macgregor (1975). Chromomere number and its genetic significance in lampbrush chromosomes. Chromosoma, 50: 327-347.
Hennen, S., S. Mizuno, and H.C. Macgregor (1975). In-situ hybridisation of rDNA labelled with 125-I to metaphase and lampbrush chromosomes of newts. Chromosoma, 50:340-360.
Macgregor, H.C., M. Vlad, and L. Barnett (1976). An investigation of some problems concerning nucleolus organisers in salamanders. Chromosoma, 59: 283-299.
Macgregor, H.C. and S. Mizuno (1976). In-situ hybridisation of 'nick-translated' 3H-ribosomal DNA to chromosomes from salamanders. Chromosoma, 54: 15-25.
Mizuno, S., C. Andrews, and H.C. Macgregor (1976). Interspecific 'common' DNA sequences in salamanders of the genus Plethodon. Chromosoma, 58: 1-31.
Macgregor, H.C. and C. Andrews (1977). The arrangement and transcription of 'middle repetitive' DNA sequences on lampbrush chromosomes of Triturus. Chromosoma, 63: 109-126.
Macgregor, H.C. (1977). Lampbrush Chromosomes. in Chromatin and Chromosome Structure., R.A. Eckhardt and Hseuh-Jei Li (Editors). pp. 339 - 357. Academic Press:
Macgregor, H.C. and C. Jones (1977). Chromosomes, DNA sequences, and evolution in salamanders of the genus Aneides. Chromosoma, 63: 1-9.
Macgregor, H.C. and G.T. Morgan (1978). Repetitive DNA and chiasma failure in chromosome I of crested newts. J. Cell Biol., 79: 133a. (Abstract)
Macgregor, H.C. (1978). Trends in the evolution of very large chromosomes. Proc. Roy. Soc. London, B 283: 309-318.
Morgan, G.T., H.C. Macgregor, and A. Colman (1979). Multiple ribosomal sites revealed by in situ hybridisation of Xenopus rDNA to Triturus lampbrush chromosomes. Chromosoma, 80: 309-330.
Macgregor, H.C. and S. Sherwood (1979). The nucleolus organisers of Plethodon and Aneides located by in-situ nucleic acid hybridisation with Xenopus 3H ribosomal RNA. Chromosoma, 72: 271-280.
Macgregor, H.C. (1979). In-situ hybridisation of highly repetitive DNA to chromosomes of Triturus cristatus. Chromosoma, 71: 57-64.
Macgregor, H.C. and L. Klosterman (1979). Observations on the cytology of Bipes (Amphisbaenia) with special reference to its lampbrush chromosomes. Chromosoma, 72: 67-87.
Macgregor, H.C. (1980). Recent developments in the study of lampbrush chromosomes. Heredity, 44: 3-35.
Varley, J.M., H.C. Macgregor, and H.P. Erba (1980). Satellite DNA is transcribed on lampbrush chromosomes. Nature, 283: 686-688.
Hill, R.S. and Macgregor, H.C. (1980). The development of lampbrush chromosome-type transcription in the early diplotene oocytes of Xenopus laevis: an electron microscope analysis. J. Cell Sci. 44, 87 - 101.
Macgregor, H.C., J.M. Varley, and G.T. Morgan (1981). The transcription of satellite and ribosomal DNA sequences on lampbrush chromosomes of crested newts., in International Cell Biology. Springer-Verlag: p. 33-46.
Macgregor, H.C. and H.A. Horner (1980). Heteromorphism for chromosome I, a requirement for normal development in crested newts. Chromosoma, 76: 111-122.
Macgregor, H.C. (1980). Recent developments in the study of lampbrush chromosomes. Heredity, 44: 3-35.
Varley, J. M., H.C. Macgregor, I. Nardi, C. Andrews and H.P. Erba (1980). Transcription of highly repeated DNA sequences during the lampbrush stage in Triturus cristatus carnifex. Chromosoma, 80: 289-307.
Macgregor, H.C. (1982). Big chromosomes and speciation amongst Amphibia. in Genome Evolution, G.A. Dover and R.B. Flavell (Editors). Academic Press: pp. 325-341.
Macgregor, H.C. (1982). Ways of amplifying ribosomal genes. in The Nucleolus. Society for Experimental Biology Seminar Series 15, E.G. Jordan and C.A. Cullis (Editors). Cambridge University Press: Cambridge. pp. 129-152.
Macgregor, H.C. and E. del Pino (1982). Ribosomal gene amplification in multinucleate oocytes of the egg brooding hylid frog Flectonotus pygmaeus. Chromosoma, 85: 475-488.
Horner, H.A. and H.C. Macgregor (1983). C value and cell volume; their significance in the evolution and development of amphibians. J. Cell Sci., 63: 135-146.
Macgregor, H.C. and J.M. Varley (1983). Working with Animal Chromosomes. John Wiley and Sons Ltd.: Chichester and New York.
Macgregor, H.C., Horner, H.A. and Sims, S.H. (1983). Newt chromosomes and some problems in evolutionary cytogenetics. Proceedings of the Kew Chromosome Conference II, Allen and Unwin. pp. 283 - 294.
Swan, A.P., H.C. Macgregor, and R. Ransom (editors) (1984). Programmes for Development. Symposium of the British Society for Developmental Biology. 1984. The Company of Biologists.
Macgregor, H.C. (1984). The lampbrush chromosomes of animal oocytes. in Chromosome Structure and Function, M. Risley, (Editor). van Rostrand and Reinhold Publishing Corp: New York. pp. 152 - 186.
Macgregor, H.C. and A.P. Swan (1984). An introduction to Programmes for Development. J.Embryol.Exp.Morph. 83(Supplement): 1-6.
Sims, S.H., H.C. Macgregor, P.A. Pellatt and H.A. Horner (1984). Chromosome 1 in crested and marbled newts genus Triturus: an extraordinary case of heteromorphism and independent chromosome evolution. Chromosoma, 89: 169-185.
Macgregor, H.C. (1984). Lampbrush chromosomes and gene utilisation in meiotic prophase. In Controlling Events in Meiosis, W. Evans and H.G.Dickinson (Editors). The Company of Biologists. pp. 333 - 348.
Macgregor, H.C. (1984). The evolutionary consequence of major genomic changes in Amphibia. In Chromosomes Today, 8 M.D.Bennett, A. Gropp, U. Wolf (Editors). George Allen and Unwin. pp. 256 - 267.
Horner, H.A. and H.C. Macgregor (1985). Normal development in newts (Triturus) and its arrest as a consequence of an unusual chromosomal situation. J. Herpetology, 19: 216 - 270.
Baldwin, L. and H.C. Macgregor (1985). Centromeric satellite DNA in the newt Triturus cristatus karelinii and related species: its distribution and transcription on lampbrush chromosomes. Chromosoma, 92: 100-107.
Macgregor, H.C. and S.K. Sessions (1986). The biological significance of variation in satellite DNA and heterochromatin in newts of the genus Triturus: an evolutionary perspective., in The Evolution of DNA Sequences, B.C. Clarke, A. Robertson and A.J. Jeffreys (Editors). Phil. Trans. R. Soc. Lond.: B 312: 53 - 70.
Macgregor, H.C. (1986). Care, maintenance and captive breeding of newts (Triturus). In UFAW Handbook, Longman. pp. 768 - 772.
Schmid, M., S.H. Sims, T. Haaf and H.C. Macgregor (1986). Chromosome banding in Amphibia X. 18S and 28S ribosomal RNA genes, nucleolus organizers and nucleoli in Gastrotheca riobambae . Chromosoma, 94: 139-145.
Macgregor, H.C. and S.K. Sessions (1986). Models for evolution of large genomes and karyotypes of urodeles. Verhandlungen der Duetzchen Zoologischen Gesellschaft., 79: 137-148.
Macgregor, H.C. (1986). The lampbrush chromosomes of animal oocytes. in Chromosome Structure and Function, M.Risley (Editor), Van Rostrand & Reinhold Publishing Corporation, New York.: pp. 152-186.
Macgregor, H.C. (1987). Lampbrush Chromosomes. J. Cell. Sci. 88: 7-9.
Macgregor, H.C. (1988). The Evolutionary Cytogenetics of Triturus (Amphibia, Urodela): An overview. In Symposium on the Evolution of Terrestrial Vertebrates, G. Chiara (Editor). Mucchi, Modena. pp. 153 - 170.
Macgregor, H.C. and J. Varley (1988). Working with Animal Chromosomes. 2nd edition. John Wiley & Sons.
Macgregor, H.C. (1988). Chromosome heteromorphism in newts (Triturus) and its significance in in relation to evolution and development. In Amphibian Cytogenetics and Evolution, D. Green and S.K.Sessions (Editors). Academic Press. pp. 175 - 196.
Sessions, S.K., H.C. Macgregor, M. Schmid and T. Haaf (1988). Cytology, embryology and evolution of the developmental arrest syndrome in newts of the genus Triturus (Caudata: Salamandridae). J. Exp. Zool. 248: 321 - 334.
Macgregor, H.C. (1990). Newts and two studies in molecular cytogenetics., in Cytogenetics of Amphibians and Reptiles, E. Olmo (Editor). Birkhauser Verlag. pp. 61-84.
Varley, J.M., H.C. Macgregor and L. Barnett (1990). Characterization of a short, highly repeated and centromerically localized DNA sequence in crested and marbled newts of the genus Triturus. Chromosoma, 100: 15 - 31.
Macgregor, H.C., S.K. Sessions, and J.W. Arntzen (1990). An integrative analysis of phylogenetic relationships amongst newts of the genus Triturus (family Salamandridae) using comparative biochemistry, cytogenetics and reproductive interactions. J. Evol. Biol. 3: 329-374.
Solovei, I., E. Gaginskaya, T.D. Allen and H.C. Macgregor (1992). A novel structure associated with a lampbrush chromosome in the chicken, Gallus domesticus. J. Cell Science, 101: 759-772.
Macgregor, H.C. (1992). Introduction to Biological Sciences. in The Pergamon Encyclopedia for Higher Education. 4: 2181 - 2183. Pergamon Press, Oxford.
Macgregor, H.C. (1992). Evolutionary Biology. In Pergamon Encyclopedia for Higher Education, 4: 2226 - 2231. Pergamon Press, Oxford.
Solovei, I., E. Gaginskaya, N. Hutchison and H.C. Macgregor (1993). Avian sex chromosomes in the lampbrush form: the ZW lampbrush bivalents from six species of bird. Chromosome Research, 1: 153-166.
Macgregor, H.C. (1993). British Universities in the World of Business. The New Academic, 3: 12-14.
Macgregor, H.C. (1993). An Introduction to Animal Cytogenetics. Chapman and Hall: London.
Macgregor, H.C. (1993). Chromosome Research - look forward to 2001. Chromosome Res., 1: 5-7.
Solovei, I., E.R. Gaginskaya, and H.C. Macgregor (1994). The arrangement and transcription of telomere DNA sequences at the ends of lampbrush chromosomes of birds. Chromosome Res., 2: 460-470.
Fairchild, P.J., Macgregor H.C. (1994). Asymmetric loops. Current Biology, 4: 919.
Solovei, I., H.C. Macgregor and E. Gaginskaya (1995). Single stranded nucleic acid binding structures on chicken lampbrush chromosomes. J. Cell Sci. 108, 1391 - 1396.
Solovei, I., H.C. Macgregor and E. Gaginskaya (1995). Specifically, terminal clusters of telomere DNA sequences are transcribed from the C-rich strand on chicken lampbrush chromosomes. Proc. Kew Chromosome Conference IV. P.F.Brandham and M.D.Bennett (eds. Royal Botanic Gardens, Kew, Press. 1995. pp. 323 - 330.
Macgregor, H.C. (1995). Crested Newts: Ancient Survivors. British Wildlife 7: 1 - 8.
Macgregor, H.C. (2011). From Bones to Biotechnology: 50 years of new biology in the Old World. In A History of the University in Europe (ed. Walter Ruegg) Volume IV, 451 – 471. Cambridge University Press.
Hori, T., Susuki, Y., Solovei, I., Saitoh, Y., Hutchison, N., Ikeda, Joh-E., Macgregor, H.C., Mizuno, S. (1996). Characterization of DNA sequences constituting the terminal heterochromatin of the chicken Z chromosome. Chromosome Res., 4: 411 - 426.
Joffe, B.I., Solovei, I. V., Macgregor, H.C. (1996). Ends of chromosomes in Polycelis tenuis (Platyhelminthes) have telomere repeat TTAGGG. Chromosome Res., 4: 323-324.
Macgregor H.C., Solovei I., and Mizuno, S. (1997) Lampbrush chromosomes as systems for high resolution studies of meiotic chromosome structure. In “Chromosome Segregation and Aneuploidy”, (ed. A. Abbondandolo, B.K.Vig and R. Roi). European Commission Joint Research Centre Publication. pp 172 - 183.
Solovei, I., Joffe, B. Gaginskaya, E., Macgregor, H.C. (1996). Transcription on lampbrush chromosomes of a centromerically localized highly repeated DNA in pigeon (Columba) relates to sequence arrangement. Chromosome Res., 4, 588 - 603.
Ogawa, A., Solovei, I., Hutchison, N., Saitoh, Y., Ikeda, J-E., Macgregor, H.C., Mizuno, S. (1997). Molecular characterization and cytological mapping of a non-repetitive DNA sequence region from the W chromosome of chicken and its use as a universal probe for sexing Carinatae birds. Chromosome Res., 5, 93 - 101.
Joffe, B., Solovei, I., Macgregor, H.C. (1998). Ordered arrangement and rearrangement of chromosomes during spermatogenesis in two species of planarians (Platyhelminthes). Chromosoma 107, 173 - 183.
Solovei, I., Joffe, B., Hori, T., Thomson, P., Mizuno, S., Macgregor, H.C. (1998). Unordered arrangement of chromosomes in nuclei of chicken spermatozoa. Chromosoma 107, 184 -188.
Mizuno, S., Macgregor H.C. (1998). The ZW lampbrush chromosomes of birds: a unique opportunity to look at the molecular cytogenetics of sex chromosomes. Cytogenet. Cell Genet. 80, 149 - 157.
Solovei, I., Ogawa, A., Naito, M., Mizuno, S., Macgregor H.C. (1998). Specific chromomeres on the chicken W lampbrush chromosome contain specific repetitive DNA sequence families. Chromosome Res., 6, 323 - 327.
Baker, S., Greig, C., Macgregor, H.C., Swan, A. (1998). Exmoor ponies: Britain's prehistoric wild horses? British Wildlife 9, 304 - 313.
Macgregor, H.C. (2000). The Future of Chromosomes. In Chromosomes Today, (E. Olmo and C.A.Redi, eds.) 13, 305 – 313. Birkhauser Verlag.
Teranishi, M., Shimada, Y., Hori, T., Nakabayashi, O., Kikuchi, T., MacLeod, T., Pym, R., Sheldon, B., Solovei, I., Macgregor, H.C., Mizuno, S. (2001). Transcripts of the MHM region on the chicken Z chromosome accumulate as non-coding RNA in the nucleus of female cells adjacent to the DMRT1 locus. Chromosome Res., 9: 147 - 165.
Sessions, S.K., Macgregor, H.C. (2009) The necessity of Darwin. Chromosome Res., 17: 437– 442.
Macgregor, H.C. (2012). Chromomeres revisited. Chromosome Res., 20: 911 – 924.
Macgregor, H.C. (2012). So what’s so special about these things called lampbrush chromosomes? Chromosome Res., 20: 903 – 904.