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Dr. Siwo R. de Kloet

 

Born:
February 22, 1933, Maarssen, The Netherlands.

Current:
1) Prof. Emeritus Biological Science
Florida State University
Tallahassee FL 32306

2) Research Director
Animal Genetics
Avian Biotech International
1336 Timberlane Road
Tallahassee, FL 32312
PH: 1-800-514-9672
e-mail: siwo@avianbiotech.com

Education:
Ph. D. in Biophysical Chemistry. University of Utrecht, The Netherlands, 1961.
Postdoctoral fellowship at the Rockefeller University, New York, NY 1961 - 1962. Isolation of messenger RNA from calf thymus.

Positions held:
1) Research Biochemist, N.V. Philips Gloeilampenfabrieken, 1963 - 1967
2) Associate Prof/Prof Biological Science, Florida State University 1967 - 1996.
3) Professor emeritus Florida State University 1996 - present.
4) Research director Avian Biotech Int. 1992 - present

Research Interests:
Avian molecular evolution and genome organization, Sex differentiation and identification of birds, Avian diseases, Bird conservation.

 

RECENT PUBLICATIONS:

Dr. de Kloet and Avian Biotech have studied and published in the following areas of avian molecular biology and genetics.

Edwin de Kloet, Siwo R. de Kloet Analysis of the Beak and Feather Disease Viral Genome Indicates the Existence of Several Genotypes Which Have a Complex Psittacine Host Specificity Archives of Virology, In Press.
ABSTRACT: A study was made of the phylogenetic relationships between fifteen complete nucleotide sequences as well as 43 nucleotide sequences of the putative coat protein gene of different strains of Beak and Feather Disease virus obtained from 39 individuals of 16 psittacine species. The species included among others, cockatoos (Cacatuini), African grey parrots (Psittacus erithacus) and peach-faced lovebirds (Agapornis roseicollis), which were infected at different geographical locations, within and outside Australia, the native origin of the virus. The derived amino acid sequences of the putative coat protein were highly diverse, with differences between some strains amounting to 50 of the 250 amino acids. Phylogenetic analysis demonstrated that the putative coat gene sequences form six clusters which show a varying degree of psittacine species specificity. Most, but not all strains infecting African grey parrots formed a single cluster as did the strains infecting the cockatoos. Strains infecting the lovebirds clustered with those infecting such Australasian species as Eclectus roratus, Psittacula kramerii and Psephotus haematogaster. Although individual birds included in this study were, where studied, often infected by closely related strains, infection by highly diverged trains was also detected. The possible relationship between BFD viral strains and clinical disease signs is discussed.

Rolf S. de Kloet, Siwo R. de Kloet Independent cessation of recombination of sex chromosomes at the spindlin locus in neognathous birds and tinamous, a palaeognathous avian family. Genetica 199: 333-342, 2003.
ABSTRACT: Tinamous (Aves, Palaeognathae, Tinamiformes) are primitive birds, generally considered to be the sister group to the ratites. Tinamous possess a W sex-chromosome, intermediate in heterochromatization between the largely euchromatic W chromosome of the ratites and the highly condensed W chromosome of the neognathous birds. Of the four genes which are known to have diverged copies on the neognathous avian W and Z chromosome (ATP5A1, CHD1, PKC and SPIN) only the spindlin gene has W- and Z-chromosomal forms in the tinamiformes. This paper describes experiments which show that the sequences of these forms are more similar to each other and to the homologous undifferentiated spindlin gene sequences in the ratite genome than to the W or Z forms of the spindlin gene in other, neognathous species. This suggests that cessation of recombination at the spindlin locus of the ancestral W and Z chromosomes of the tinamiformes and the neagnathous avian species were independent events.

de Kloet, SR (2002) Molecular sex identification of tinamous with PCR using primers erived from the spindlin gene. Molecular Ecology Notes 2:465 - 466.
ABSTRACT: This paper describes results which show that the spindlin gene has different forms on the tinamid W and Z chromosome, providing a sensitive and accurate procedure for a molecular, PCR-based, procedure for sex-identification of tinamous
.

de Kloet, SR. (2001c) A repetitive DNA sequence on the W chromosome of owls (Strigiformes) with sequence similarity to the chicken W chromosomal repeat. The Auk, submitted

de Kloet, SR (2001b). Development of a CAPS (Cleaved Amplified Polymorphics Sequence) assay for sex identification of the emu (Dromaius novaehollandiae). Molecular Ecology Letters 1: 273 - 275.
ABSTRACT: Polymerase chain rection (PCR) based procedures that have been used to identify the sex of most birds cannot be used in ratites. This paper described the identification of a female (W-chromosomal) specific randomly amplified polymorphic (RAPD) 1.3 kb DNA fragment (ESEXW) in the emu (Dromaius novaehollandiae). Southern blot experiments and sequence analysis revealed that a related (96% similarity) sequence exists of the emu Z-chromosome (ESEXZ). The sequences of ESEXW and ESEXZ have been used for the development of a two-primer CAPS (cleaved amplified polymorphic sequence) assay for reliable sex identification of the emu.

de Kloet, SR. (2001a) Loss of the gene of the alpha subunit of ATP synthase (ATP5A1) from the W chromosome of the African grey parrot (Psittacus erithacus). Journal of Molecular Evolution 53: 135 - 143.
ABSTRACT: This study describes the results of an analysis using Southern blotting, the polymerase chain reaction, and sequencing which shows that the African grey parrot (Psittacus erithacus) lacks the W-chromosomal gene for the alpha subunit of mitochondrial ATP synthase (ATP5A1W). Additional evidence shows that in other psittacines a fragment of the ATP5A1W gene contains five times as many nonsynonymous nucleotide replacements as the homologous fragment of the Z gene. Therefore, whereas in these other psittacines the corresponding ATP5A1Z protein fragment is highly conserved and varies by only a few, moderately conservative amino acid substitutions, the homologous ATP5A1W fragments contain a considerable number of, sometimes highly nonconservative, amino acid replacements. In one of these species, the ringneck parakeet (Psittacula krameri), the ATP5A1W gene is present in an inactive form because of the presence of a nonsense codon. Other changes, possibly leading to an inactive ATP5A1W gene product, involve the substitution of arginine residues by cysteine in the ATP5A1W protein of the mitred conure (Aratinga mitrata) and the blue and gold macaw (Ara ararauna). The data suggest also that although the divergence of the psittacine ATP5A1W and ATP5A1Z genes preceded the origin of the psittacidae, this divergence occurred independently of a similar process in the myna (Gracula religiosa), the outgroup used in this study.

Shi L, Drummond P, de Kloet SR, Pimentel-Smith GE, Smith EJ (2000). Comparative sequence analysis of genetic variation in the African grey parrot (Psittacus erythacus). Genetica 110: 226 - 230.
ABSTRACT: Comparative genome analysis promises to provide an insight into avian species that have been very little studied. To test the feasibility of this approach, we investigated the use of heterologous primers to generate single nucleotide polymorphisms (SNP) in the African grey parrot, Psittacus erythacus, using primers specific for chicken and turkey DNA fragments. Three of the primers were specific for three expressed sequence tagged sites in the turkey and the fourth for a chicken proteoglycan core protein-like DNA sequence. A total of about 2200 bp of the parrot genome was evaluated for DNA sequence variation. Seven SNPs were identified and confirmed by Mendelian segregation. The frequency distribution of the most common nucleotide at each SNP locus in an unrelated group of parrots ranged from 0.84 to 0.97. The percent similarity of each parrot sequence to the reference sequence was inconsistent and ranged from zero to 100%. The primers as well as the nucleotide variants described represent valuable resources for genetic analysis in the parrot.

Madsen CS, de Kloet E, de Kloet SR. (1994). Sequence conservation of an avian centromeric repeated DNA component. Genome 35: 1037 - 1044.
ABSTRACT: The approximately 190-bp centromeric repeat monomers of the spur-winged lapwing (Vanellus spinosus, Charadriidae), the Chilean flamingo (Phoenicopterus chilensis, Phoenicopteridae), the sarus crane (Grus antigone, Gruidae), parrots (Psittacidae), waterfowl (Anatidae), and the merlin (Falco columbarius, Falconidae) contain elements that are interspecifically highly variable, as well as elements (trinucleotides and higher order oligonucleotides) that are highly conserved in sequence and relative location within the repeat. Such conservation suggests that the centromeric repeats of these avian species have evolved from a common ancestral sequence that may date from very early stages of avian radiation.

Tuohy JM, McHugh KP, deKloet SR. (1992). Systematic relationships among some Anatini as derived from restriction endonuclease analysis of a repeated DNA component. The Auk 109: 465 - 473.

Madsen CS, McHugh KP, de Kloet SR. (1992). Characterization of a Major Tandemly Repeated DNA Sequence (RBMII) Prevalent Among Many Species of Waterfowl (Anatidae). Genome 35:1037 - 1044.
ABSTRACT: We have investigated the evolution of a 190 base pair tandemly repeated DNA sequence (RBMII) in 27 different species of waterfowl. In this paper we show that the RBMII sequence is present in many species belonging to 7 of the 11 Anatid tribes. Inter- and intra-tribal differences in repeat presence indicate that, although the RBMII sequence has been maintained among widely divergent species, it is rapidly evolving. Restriction enzyme analyses suggest very different hierarchical repeat organizations among different species. DNA sequence comparisons of 32 cloned monomer units from five different species revealed what appears to be a nonrandom distribution of sequence divergence, as well as large differences (up to 25-fold) in intraspecific sequence variation between relatively closely related species.

PMID: 1473722 [PubMed - indexed for MEDLINE]

Madsen CS, de Kloet DH, Brooks JE, de Kloet SR (1992). Highly repeated DNA sequences in birds: the structure and evolution of abundant, tandemly repeated 190 bp DNA fragment in parrots. Genomics 14: 462 - 469.
ABSTRACT: Up to 6.8% of the parrot (Psittaciformes) genome consists of a tandemly repeated, 190-bp sequence (P1) located in the centromere of many if not all chromosomes. Monomer repeats from 10 different psittacine species representing four subfamilies were isolated and cloned. The intraspecific sequence variation ranged from 1.5 to 7%. The interspecific sequence variation ranged from less than 3% between two species of cockatoos to approximately 45% between cockatoos and other parrots. The monomer sequences of all 10 parrot species contained several conserved (> 90%) sequence elements at identical locations within the repeat. A comparison with tandemly repeated DNA sequences in other avian species showed that several of these conserved elements were also present at similar locations within the 184-bp repeat of the Chilean flamingo (Phoenicopterus chilensis), suggesting a great antiquity of the repeat. One of the elements was also found in the tandemly repeated sequences of the crane (Gruidae) and falcon (Falconidae) families. The data were used for the construction of a partial most parsimonious relationship that supports a regional subdivision of the Psittaciformes.

de Kloet DH, de Kloet SR (1992). Molecular Determination of the Sex of Parrots. Focus (BRL) 14: 106 - 108.

McHugh KP, Madsen CS, de Kloet SR. (1990). A highly repeated retropseudogene-like sequence in DNA of the red-breasted merganser (Mergus serrator). Gene 87: 193 - 197.
ABSTRACT: We have investigated the evolution of a 190 base pair tandemly repeated DNA sequence (RBMII) in 27 different species of waterfowl. In this paper we show that the RBMII sequence is present in many species belonging to 7 of the 11 Anatid tribes. Inter- and intra-tribal differences in repeat presence indicate that, although the RBMII sequence has been maintained among widely divergent species, it is rapidly evolving. Restriction enzyme analyses suggest very different hierarchical repeat organizations among different species. DNA sequence comparisons of 32 cloned monomer units from five different species revealed what appears to be a nonrandom distribution of sequence divergence, as well as large differences (up to 25-fold) in intraspecific sequence variation between relatively closely related species.

Madsen CS, McHugh KP, de Kloet SR. (1988). A partial classification of waterfowl (Anatidae) based on single copy DNA. The Auk 105: 452 - 459.

 

 

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