ABSTRACT
A mutant allele of the maize brittle-1 (bt1) locus, brittle-1-mutable (bt1-m), was shown genetically and molecularly to result from the insertion of a defective Suppressor-mutator (dSpm) transposable element. An Spm-hybridizing restriction enzyme fragment, which cosegregates with the bt1-m allele and is absent from wild-type revertants of bt1-m, was identified and cloned. Non-Spm portions of it were used as probes to identify wild-type (Bt1) cDNAs in an endosperm library. The 4.3-kb bt1-m genomic clone contains a 3.3-kb dSpm, which is inserted in an exon and is composed of Spm termini flanking non-Spm sequences. RNA gel blot analyses, using a cloned Bt1 cDNA probe, indicated that Bt1 mRNA is present in the endosperm of developing kernels and is absent from embryo or leaf tissues. Several transcripts are produced by bt1-m. The deduced translation product from a 1.7-kb Bt1 cDNA clone has an apparent plastid transit peptide at its amino terminus and sequence similarity to several mitochondrial inner-envelope translocator proteins, suggesting a possible role in amyloplast membrane transport.
Subject(s)
Membrane Proteins/genetics , Plant Proteins/genetics , Suppression, Genetic , Zea mays/genetics , Alleles , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA , DNA Transposable Elements , Membrane Proteins/metabolism , Molecular Sequence Data , Phenotype , Plant Proteins/metabolism , Sequence Homology, Amino AcidABSTRACT
A study of diaphragmatic hernia in Avon suggests that the incidence of this malformation is increasing. The incidence in Avon from 1974 to 1977 was 0.54 per 1000 births, higher than any previously published figure for the incidence of diaphragmatic hernia.
Subject(s)
Hernia, Diaphragmatic/epidemiology , Central Nervous System/abnormalities , England , Female , Genetic Testing , Humans , Male , Sex RatioABSTRACT
Two sibs who both had anencephaly and diaphragmatic hernia are reported. The type of diaphragmatic defect seen in anencephaly may differ from the defect seen in other babies. It is important to perform a necropsy in anencephaly.
Subject(s)
Anencephaly/genetics , Hernia, Diaphragmatic/genetics , Adult , Female , Hernias, Diaphragmatic, Congenital , Humans , Infant, Newborn , MaleABSTRACT
A retrospective anatomical, family, and epidemiological study was made of 143 patients (81 female and 62 male) with diaphragmatic hernia who were born in the south-west of England between 1943 and 1974. Thirty-nine cases were stillborn. Seventy-five per cent of patients had a left-sided diaphragmatic defect, 22% had a right-sided defect, and 3% had a bilateral defect. Fifty per cent of the patients had other congenital malformations, most frequently of the nervous system. No maternal age or birth order effect was noted. Cases of diaphragmatic hernia without other malformations had in general a normal fetal growth rate. Eight per cent of the cases were illegitimate. There were two pairs of twins discordant for diaphragmatic hernia, one pair being dizygotic and the other monozygotic. In no case of diaphragmatic hernia was there a relative affected with a diaphragmatic hernia. The most common type of diaphragmatic defect was a posterolateral hernia (92%), followed in frequency by an eventration of the diaphragm (5%), the least common defect being a retrocostosternal hernia (2%). Diaphragmatic hernia appears to be aetiologically as well as anatomically heterogeneous. In this series there were two cases of trisomy 18, one case of trisomy 21, one case trisomic for a small part of chromosome 20, and two cases with the Pierre Robin syndrome. It seems likely that diaphragmatic hernia is a non-specific consequence of several teratological processes.
