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Test tube mother has girl  2010-07-28 21:00:00

Mrs Lesley Brown, the world's first test-tube mother, gave birth to a baby girl at Oldham General Hospital, Lancashire, last night after a caesarian section delivery. The historic birth took place shortly before midnight. The baby weighed in at 5lb 12ozs.

Medical staff said later that the condition of both mother and daughter were "excellent". The birth was slightly premature – it was due on 4 August. Last week Mrs Brown (32) was found to be suffering from toxemia, a mild form of blood poisoning, and there was speculation that her gynaecologist, Mr Patrick Steptoe, would hasten the birth to avoid complications.

The toxemia followed a month-long crisis for Mr Steptoe when Mrs Brown was found to be suffering from a hormone deficiency which threatened to starve the unborn baby of oxygen. 

When Mrs Brown was presented with her long-awaited child today it was not the first time she had seen her. Earlier this month she saw the fully formed baby in her womb with the help of an ultrasonic scanner. Doctors have also known the sex of the child, but at her own request Mrs Brown was not told until the birth.

The end of Mrs Brown's confinement is not likely to end the newspaper controversy which has blemished what is otherwise a high-point in British medical history.

Since news of the impending birth was first broken by an American newspaper in April, journalists from Japan, the US as well as Fleet Street have been wrangling over the "rights" to the big story.

The Daily Mail finally offered a reputed £325,000 and mounted its own guard on Mrs Brown's ward to protect the booty. Then, after a row which reached ministerial level, health authorities agreed that news of Mrs Brown's progress would be released on a normal, non-selective basis.

The test-tube baby breakthrough is the product of the research Mr Steptoe, whose unit is at Oldham, and a Cambridge physiologist, Dr Robert Edwards, have been conducting since the 1960s. Properly known as an "embryo transfer" the technique involves the removal of an egg from the mother, its fertilisation with the father's sperm, its growth in a culture medium and then its re-implantation in the mother's womb.

The operation is highly expensive, but Mr Steptoe believes several thousand women a year could soon be benefiting from it. He used the technique with Mrs Brown after she and her husband, 38-year-old lorry driver, Mr Gilbert Brown, had tried unsuccessfully for nine years to have a baby.

Via: guardian.co.uk

 

The Evolution Of Eggs And Sperm  2010-07-28 20:59:38

Have you ever wondered why most sexually reproducing organisms have two contrasting sex cells: big, immobile eggs in females and plenty of small motile sperms in men? Scientists have at last disclosed the secrets behind the reproductive science.

James Umen and colleagues at the Salk Institute for Biological Studies in California, examined related algae – the single-celled Chlamydomonas reinhardtii and the multicellular Volvox carteri, which diverged from each other 200 million years ago.

Both types are known to reproduce sexually under certain conditions. While V. carteri reproduces through the fusion of a large female egg and small male sperm, C. reinhardtii's sex cells are of a same size and cannot be categorized as male or female.

The process in each case is controlled by a genetic sequence known as the Mating Locus, or MT, which the researchers hoped would yield clues as to why the sex cells produced by the two types of algae are poles apart.

The researchers compared the MT regions of both algae by examining the RNA sequences produced by each. They found that although V. carteri's genome is just 17 per cent bigger than that of C. reinhardtii, its MT region is five times larger.

Although, some of the genes identified were common to both, the team identified five new genes present only in V. carteri's female MT and eight new male genes.

Crucially, although these are completely new, the team found similar genes with non-sex roles close to the MT area in the genome of C. Reinhardtii. It looks as if Volvox had translocated these genes into its MT area, and over time they have gained new functions related to sex.

"The genes evolve rapidly in sex-specific ways," said Umen, who believes they accumulate mutations over time. A beneficial mutations must have lead to larger eggs and smaller, plentiful sperm.

Via: living.oneindia.in

 


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Functional structure of a gene

All genes have regulatory regions in addition to regions that explicitly code for a protein or RNA product. A regulatory region shared by almost all genes is known as the promoter, which provides a position that is recognized by the transcription machinery when a gene is about to be transcribed and expressed. A gene can have more than one promoter, resulting in RNAs that differ in how far they extend in the 5′ end.[14] Although promoter regions have a consensus sequence that is the most common sequence at this position, some genes have “strong” promoters that bind the transcription machinery well, and others have “weak” promoters that bind poorly. These weak promoters usually permit a lower rate of transcription than the strong promoters, because the transcription machinery binds to them and initiates transcription less frequently. Other possible regulatory regions include enhancers, which can compensate for a weak promoter. Most regulatory regions are “upstream”—that is, before or toward the 5′ end of the transcription initiation site. Eukaryotic promoter regions are much more complex and difficult to identify than prokaryotic promoters.

Many prokaryotic genes are organized into operons, or groups of genes whose products have related functions and which are transcribed as a unit. By contrast, eukaryotic genes are transcribed only one at a time, but may include long stretches of DNA called introns which are transcribed but never translated into protein (they are spliced out before translation). Splicing can also occur in prokaryotic genes, but is less common than in eukaryotes.[15
WordPress Introduction

A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cells and pass genetic traits to offspring. A modern working definition of a gene is “a locatable region of genomic sequence, corresponding to a unit of inheritance, which is associated with regulatory regions, transcribed regions, and or other functional sequence regions “.[1] Incorrect colloquial usage of the term gene may actually refer to an allele: a gene is the basic instruction, a sequence of DNA, while an allele is one variant of that instruction.

The still evolving notion of a gene[2], has evolved with the science of genetics, which began when Gregor Mendel noticed that biological variations are inherited from parent organisms as specific, discrete traits. The biological entity responsible for defining traits was termed a gene, but the biological basis for inheritance remained unknown until DNA was identified as the genetic material in the 1940s. All organisms have many genes corresponding to many different biological traits, some of which are immediately visible, such as eye color or number of limbs, and some of which are not, such as blood type or increased risk for specific diseases, or the thousands of basic biochemical processes that comprise life.

In cells, a gene is a portion of DNA that contains both “coding” sequences that determine what the gene does, and “non-coding” sequences that determine when the gene is active (expressed). When a gene is active, the coding and non-coding sequences are copied in a process called transcription, producing an RNA copy of the gene’s information. This piece of RNA can then direct the synthesis of proteins via the genetic code. In other cases, the RNA is used directly, for example as part of the ribosome. The molecules resulting from gene expression, whether RNA or protein, are known as gene products, and are responsible for the development and functioning of all living things.

In more technical terms, a gene is a locatable region of genomic sequence, corresponding to a unit of inheritance, and is associated with regulatory regions, transcribed regions and/or other functional sequence regions.[3][4] The physical development and phenotype of organisms can be thought of as a product of genes interacting with each other and with the environment.[5] A concise definition of a gene, taking into account complex patterns of regulation and transcription, genic conservation and non-coding RNA genes, has been proposed by Gerstein et al.:[6] “A gene is a union of genomic sequences encoding a coherent set of potentially overlapping functional products”.