Little is known about the function of amyloid precursor protein. 1. Definition. Ultimately, one wishes to determine how genes—and the proteins they encode—function in the intact organism. Genes are DNA sections that code for specific proteins or functional RNA, playing a crucial part in. The exception is Krystal Biotech (), which gained approval in May for a gene therapy that treats a skin disease. Hereditary Breast and Ovarian Cancer. In some cases, the answer is yes. Approximately 90% of canola, cotton, corn, soybean, and sugar beets grown in North America are transgenic. Escherichia coli strain K-12 is arguably the single organism about which the most is known. Enzyme complexes that break down protein are called _____. We find that local genetic variation affects gene expression levels for the majority of genes, and we further. It involves copying a gene's DNA sequence to make an RNA molecule. November 25, 2018. Dawkins revealed in the first volume of his memoirs, An Appetite for Wonder (Bantam, 2013; see E. Mechanisms: the processes of evolutionSelection, mutation, migration, and more. Reels. New research suggests it is possible to slow or even reverse aging, at least in mice, by undoing changes in gene activity—the same kinds of changes that are caused by decades of life in humans. DNA cloning is the process of making multiple copies of a particular segment of DNA. Gregor Mendel was a scientist and Augustinian friar who lived in what is now the Czech Republic; he's considered the father of modern genetics due to his plant hybridization experiments. “We feel it’s critical that the scientific community. The type and amount of melanin in hair is determined by many genes, although little is known about most. Cancer is often the result of changes in more than one of these types of. Genes are sections of DNA that carry instructions to make a protein. DNA methylation is associated with developmental changes and. Gene Back is a Korean-American film composer and multi-instrumentalist. 2. The majority of genes carried in a cell's DNA specify the amino acid sequence of proteins; the RNA molecules that are copied from these genes (which ultimately direct the synthesis of proteins) are called messenger RNA (mRNA) molecules. A gene is a segment of DNA that contains instructions for building one or more molecules that help the body work. In this week’s science newsletter, explore the latest developments in human gene editing, marvel at bees’ dance moves, learn about zombie viruses, meet the first people to ride horses, and more. the influence of environment on development. Dec. gov when relevant: table2asn, a. New DNA. Before sharing sensitive information, make sure you're on a federal government site. [1] Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration, and this complex links the glycolysis metabolic pathway to the. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. There, the process of _____ creates a molecule of RNA from a. 9%. What is Epigenetics? Your genes play an important role in your health, but so do your behaviors and environment, such as what you eat and how physically active you are. The distinctive combinations of genes our cells keep switched on help to commit them to becoming muscle, skin, or some other part of the body. Have you ever looked at a calico cat and wondered how it got its multicolored coat? Or have you wondered why more boys than girls are colorblind? The combination of colors in the cat, and the reason some people are more likely to have traits like colorblindness or to get certain diseases, all comes back to one little part of the body, the X chromosome! Learning more about how our genes make us. Figure 13. Join Pop Mech Pro. (2013, July 15) The Epigenome at a Glance. The main types of genes that play a role in cancer are: Oncogenes. Mendelian Genetics is a kind of biological inheritance that highlights the laws proposed by Gregor Mendel in 1866 and rediscovered in 1900. Anna Kerrigan) and "Holler" (dir. Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Bargmann watches two colleagues manipulate a microscopic roundworm. In this process: mRNA is transcribed from genes; then the mRNA transcripts are delivered to. Sharp First published in Fall 2002 Double Helix Network News Rev. Weekend magazine, launched in October 1993, is issued free with the Saturday Daily Mail. and among the highest globally. A top FDA official said Monday that the agency needs to consider accelerated approval, a regulatory avenue commonly used to expedite the market entry of cancer drugs, for gene therapies. Prokaryotes control protein levels using epigenetic modifications whereas eukaryotes control protein levels by regulating the rate of transcription and translation. Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. DNA holds the instructions for building the proteins that carry out a variety of functions in a cell. Five persons linked to this address. The first of these glyphosate-resistant crops was a variety of soybean, engineered by Monsanto in 1996. The Selfish Gene is a 1976 book on evolution by the ethologist Richard Dawkins, in which the author builds upon the principal theory of George C. The first American composer to have been selected as a British Academy of Film and Television Arts (BAFTA) Breakthrough talent, his work spans. Restriction enzymes. Now glyphosate-resistant technology has been applied to many other crops, including corn and. "Definition of itback in the Definitions. For example, it can be used to: Identify differences between knockout and control samples. This protein is found in many tissues and organs, including the brain and spinal cord (central nervous system). GenBank ® is the NIH genetic sequence database, an annotated collection of all publicly available DNA sequences ( Nucleic Acids Research, 2013 Jan;41 (D1):D36-42 ). 1 The student can connect phenomena and models across spatial and temporal scales. Pyruvate dehydrogenase complex. Genes are turned on and off in different patterns during development to make a brain cell look and act different from a liver cell or a muscle cell, for example. It includes structural genes (generally encoding enzymes), regulatory genes (encoding, e. These are usually treated separately as the nuclear genome and the mitochondrial genome. The swiftness of this change is being driven by innovations such as CRISPR gene editing,. Reproductive isolation - Understanding Evolution. 4,668 likes, 47 comments - itsgeneback2. However, phenotypic reversion can result…. These studies investigate the origins of various Jewish ethnic divisions. What Darwin Got Wrong by Jerry Fodor and Massimo. Two possibilities for recombination between two nonsister chromatids during meiosis are shown in Figure 17. There are various kinds of RNA. Different cells in a multicellular organism may express very different sets of genes, even though they contain the same DNA. The Food and Drug Administration has cleared Pfizer to resume dosing patients with an experimental hemophilia gene therapy that was put on hold last year because of the risk of dangerous blood clots, the company announced Tuesday. This timeline presents a concise history of the seminal contributions and the scientists who pushed this field forward, from the initial discovery. Transcriptional access to the DNA can be controlled in two general ways: chromatin remodeling and DNA methylation. They got more than they wanted. The human genome, which is typical of the genomes of all. The epigenome is a multitude of chemical compounds that can tell the genome what to do. Different cells in a multicellular organism may express very different sets of genes, even though they contain the same DNA. D. An abundance of another pigment, called pheomelanin, gives people red hair. The trial, XIRIUS, evaluated BIIB112 as a one-time therapy for patients with XLRP. Genetics and Health. A relative with cancer has a diagnostic blood test to see if they have a cancer risk gene (this must happen before any healthy relatives are tested). Eukaryotic gene expression begins with control of access to the DNA. And a booster identified as “Uncle T” is alleged to have at least partially funded former analyst Connor. gov or . Editor's Note: This is the first in a series of six features on the science of food, running daily from March 30 through April 6, 2009. Ultimately, one wishes to determine how genes—and the proteins they encode—function in the intact organism. However, in 2006, scientists reported that they had turned a differentiated cell. 251. Summary: Researchers have found that DNA mutations are not. DNA is made up of nucleotides, each nucleotide has three components: a backbone made up of a sugar. Researchers are closing in on the long-sought goal of creating high-yielding hybrid crops that can be propagated indefinitely, without sex. . It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. nih. The irises of human eyes exhibit a wide spectrum of colours. The dun gene lightens most of the body while leaving the mane, tail, legs, and. Each restriction enzyme recognizes a specific sequence, usually of four or six nucleotides in the DNA. Supplementary files in Excel format from 18 journals published from 2005 to 2015 were programmatically screened for the presence of gene name errors. This definition was built on the classical concept of “epigenesis,” which was introduced around 1650 by William. Cancer begins when some of the genes in a cell become abnormal, causing the cell to grow and divide out of control. The type of control is defined by the response of the operon when no regulatory protein is present. The SHH gene provides instructions for making a protein called Sonic Hedgehog. By Nicholas Wade. This is how one cell might end up being important to your kidneys, while another cell makes bone. This can lead to severe developmental abnormalities, cancer, and other problems. The genetic makeup of an organism (ex: TT) Phenotype. Gene regulation is the process of controlling which genes in a cell's DNA are expressed (used to make a functional product such as a protein). A family of DNA methyltransferases (Dnmts) catalyzes the transfer of a methyl group from S-adenyl methionine (SAM) to the fifth carbon of cytosine residue to form 5-methylcytosine (5mC). A scanning electron micrograph of a human embryonic. Researchers have cloned a wide range of biological materials, including genes,. The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. Ever since. (4) Antioxidant Genes. mil. Eukaryotic gene expression begins with control of access to the DNA. The Hardy-Weinberg law is named in honor of the two men who first realized the significance of the binomial expansion to population genetics and hence to evolution. Genetic factors. Studying Gene Expression and Function. With estimates of losing 15 to 40 percent of the world’s species over the next four decades – due to climate change and habitat loss, researchers ponder in the Sept. Gene therapy developer Solid Biosciences is laying off 35% of its employees, announcing Wednesday a plan to extend its current funds for another two years as a sector-wide downturn limits financing options. Learn the fascinating origin of the Geneback surname; its meaning & distribution. Génesis Gonzalez - @ge_nesis8081. Scientists hope to alter cowpea seedlings so the crop can. Reverse mutation from the aberrant state of a gene back to its normal, or wild type, state can result in a number. Mutations in the BRAF gene could cause an impaired protein function, depending on localization and type [ 13 ]. Therefore, the thousands of genes expressed in a particular cell determine what that cell can do. Gregor Mendel's first principle of genetic inheritance. In June 2000, when the results were announced at a White House ceremony, Craig Venter, a pioneer of DNA sequencing, observed, “The concept of race has no genetic or scientific basis. Genome and Transcriptome Assemblies can be submitted through the Genomes and TSA portals, respectively. 1. DNA methylation pathways. He proposed that CRISPRs serve as part of the bacterial immune system, defending against invading viruses. Gene mutation examples include severe genetic disorders, cell overgrowth, tumor formation and heightened risk of breast cancer. There are various kinds of RNA. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nucleus. Cystic fibrosis is caused by mutations in the gene responsible for producing the cystic fibrosis transmembrane conductance regulator (CFTR) protein. In vivo (inside your body): Scientists put the vector carrying the new genes directly into your body via an injection or intravenous (IV) infusion. A “blue” dun, or grullo. 2A). The cost is $850,000 WAC. DNA is composed of different sequences of our genes. While an embryo grows, arms and legs develop differently due to the actions of homeotic genes, which specify how structures develop in. May 19, 2021 - Biogen recently announced that its gene therapy for X-linked retinitis pigmentosa (XLRP), Cotoretigene toliparvovec (BIIB112), failed in a Phase 2/3 study. The instructions for making proteins are carried in a person’s genetic code, and variants (or mutations) in this code can impact the production or function of. Hustle culture has commonly glorified long hours of work to succeed (Credit: Getty Images) Some data also shows employees are leaning out instead of going all in. For this reason, scientists are exploring ways to provide a correct. ” For decades, scientists have dismissed these sequences as useless or “junk” DNA. 2. Taking a supplement with more than. RNA-sequencing is a powerful technique that can assess differences in global gene expression between groups of samples. Gene regulation is the process of controlling which genes in a cell's DNA are expressed (used to make a functional product such as a protein). Gene changes that start in a single cell over the course of a person's life cause most cancers. The primary gene pool consists of G. Stem cell researchers reactivate 'back-up genes' in the lab. genetic mutations. 1 / 21. Theoretical, anthropological and genetic studies suggest that human evolution has been shaped by gene–culture interactions. g. The film is based on the 1991 novel of the same name by author John Grisham. March 2013 What dog breeders do is not breeding dogs; normal, healthy dogs can do that without any assistance from us. Short interfering RNA (siRNA) pathway is a RNAi pathway, where exogenous double stranded RNA is introduced to the cell and cleaved by. Breeders manipulate genes, encouraging some to pass on from generation to generation while at the same time trying to prevent others. The instructions for making proteins are carried in a person’s genetic code, and variants (or mutations) in this code can impact the production or function of. Here we describe genetic effects on gene expression levels across 44 human tissues. Restriction enzymes and DNA ligase are used in the process. The essential classic country playlist ©David Redfern/Redferns. One of different forms of a gene. Its Genes May Tell Us How. July 27, 2020 , by NCI Staff. Recessive Gene Definition. Until fairly recently, cell differentiation was seen as final and irreversible. Study with Quizlet and memorize flashcards containing terms like Enzyme complexes that break down protein are called _____. This. Based on features of the data, the research team concluded that migrations from ancient Europeans back into Africa introduced Neanderthal ancestry into African populations. This definition was built on the classical concept of “epigenesis,” which was introduced around 1650 by William. Gene regulation is key to the ability of an organism to respond to environmental. Genes and alleles, two fundamental concepts in genetics, differ in their roles. S. What happens is that two chromosomes, one from each parent, pair up with each other. The CRISPR arrays allow the bacteria to "remember. The early characterization of the molecule, including its. Trilobites. Strands of DNA make up part of your chromosomes. The nuclear membrane's role in the. In the last 20 years, there have been major advances in our understanding of the underlying genetic risk for SLE, with >80 established susceptibility loci. 1007/978-1-0716-1217-0_10. Originally isolated in 1922, it was catapulted to prominence by the discovery of strain K-12's ability to carry out genetic recombination by conjugation ( 1) and, soon after, by generalized transduction ( 2 ). Researchers at King's College London have for the first time identified a gene linked to age-related degeneration of the intervertebral discs in the spine, a common cause of lower back. This week, we spotlight Gene Back, a Korean-American film composer, multi-instrumentalist, and BAFTA Breakthrough Talent, whose collaborative work spans from Talib Kweli to the Orchestra Roma. Some observers argue that the real problem wasn’t him—it was the lure of the technology. genetic mutations. Gene therapy holds promise for treating a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS. The relative merits of hypotheses in which genetic change comes first and triggers a cultural response, or vice versa, can be evaluated by extracting ancient DNA from ancestral populations, as. These mice, it seems, have sipped from a fountain of youth. Although it may sound counterintuitive, one of the most direct ways to find out what a gene does is to see what happens to the organism when that gene is missing. Types of Pandas. [1] Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. One jellyfish’s regeneration powers seem linked to key genetic changes. A recessive gene is a gene whose effects are masked in the presence of a dominant gene. 4. Results We hypothesize that. DNA is the hereditary material in humans and almost all other organisms. In the process, they may cause mutations and increase (or decrease) the amount of DNA in the genome of the cell, and if the cell is the precursor of a gamete, in the genomes of any descendants. step. These levels of chromatin compaction are illustrated here in two chromosomes (orange and blue). DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor (s) to DNA. The drugmaker, which is developing the gene therapy with Sangamo Therapeutics, said it hopes to begin treating. Campaigners representing UK business, farming, certification, academia, and science have lodged a complaint against the UK’s Food Standards Agency (FSA), raising concerns about its public consultation process on precision bred organisms for use in animal feed and food. Cells are the body’s building blocks. He also leads Accenture’s global CMO community of 650+ senior-most marketing leaders who gather. Types of gene therapy. A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. 8 million, making the therapy the most expensive drug on a single-use basis in the U. An immortal species of jellyfish has double copies of genes that protect and. 3. In this case, it involves crossing-over. Just as a recipe can be used to make a dish of food, a gene can be used to make a protein, a building block. Gene therapy replaces a faulty gene or adds a new gene in an attempt to cure disease or improve your body's ability to fight disease. DNA, or Deoxyribonucleic acid, is the genetic code that determines traits in organisms. genesis Ella nos pidió para su negocio!! Gracia. A red dun. Transcriptional access to the DNA can be controlled in two general ways: chromatin remodeling and DNA methylation. 26. We would like to show you a description here but the site won’t allow us. Higher activities of the UPS appear to retard aging effects [ 13, 14 ]. Researchers or farmers can withdraw samples from these “gene” banks to help rebuild populations of rare plant varieties and animal breeds or to help increase genetic diversity within species. Gene therapy developer Solid Biosciences is laying off 35% of its employees, announcing Wednesday a plan to extend its current funds for another two years as a sector-wide downturn limits financing options. Genetic banks serve a similar purpose for farmers and scientists who work to conserve rare plants and animals. Gene replacement therapy is the technique of recognizing a faulty gene, applying a piece of DNA in its correct form though a viral vector (known as the carrier molecule) to the gene, thus overriding. The sequence of the bases (often referred to. Submission preparation tools which require uploading via the Submission Portal or email to gb-sub@ncbi. However, male genes are much more aggressive than female genes, that’s why they are usually more prominent. A recessive gene is only expressed when an. Genes are made of DNA. This combination of your genetics and experiences ultimately forms your identity and. Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. MOST parents dream of a 5-week-old baby who sleeps through the night, but. The set of genes expressed in a cell determines the set of proteins and. Most genomes, including the human genome and those of all other cellular life forms, are made of DNA (deoxyribonucleic acid) but a few viruses have RNA (ribonucleic acid) genomes. ”. He is the author of many books including the international best-sellers "The Selfish Gene", "The Blind. The company also intends to narrow the focus of its research and development efforts to just two gene therapy projects and next-generation. The nuclear membrane's role in the regulation of gene expression involves. Results of random union of the gametes produced by an entire population with a gene pool containing 80% B and 20%. Ma et al. A person’s diet is an. The company claims that its techniques to. Breast cancer: About 13% of women in the general population will develop breast cancer sometime during their lives ( 1 ). Alternative splicing generates transcriptome diversity and enables gene regulation. The major type, called messenger RNA (mRNA), plays a vital role in making proteins. Internal transcribed spacer ( ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the. Background Eukaryotic genomes undergo pervasive transcription, leading to the production of many types of stable and unstable RNAs. The SARS-CoV-2 genome consists of nearly 30,000 RNA bases. Transcription Produces RNA Complementary to One Strand of DNA. To make a transgenic cell, DNA must first be transferred. Genotype. Richard Dawkins is Professor of the Public Understanding of Science at Oxford University. The trial, XIRIUS, evaluated BIIB112 as a one-time therapy for patients with XLRP. 0 on September 17, 2023: "Que tal tu finde? @itsgeneback". . The process can be complicated and is carried out by a variety of mechanisms, including through regulatory proteins and chemical modification of DNA. wild type is called a back mutation or reversion. ”. Prasoon Pandey, Neelam Balekar, in Drug Targeting and Stimuli Sensitive Drug Delivery Systems, 2018. Genes encode proteins and proteins dictate cell function. Answer: B. 10. Gene regulation is an important part of normal development. The External RNA Controls Consortium (ERCC) developed a set of universal RNA synthetic spike-in standards for microarray and RNA-Seq experiments ( Jiang et al. For 8-character character accessions (e. DNA: Properties, Structure, Composition, Types, Functions. Three decades after its first, faltering steps in humans, gene therapy is emerging as a treatment option for a small but growing number of diseases. Although it may sound counterintuitive, one of the most direct ways to find out what a gene does is to see what happens to the organism when that gene is missing. net dictionary. 2015 ). Gene Back. 114. Every organism that has DNA packed into chromosomes has two alleles, or forms of a gene, for each gene: one inherited from their mother, and one inherited from their father. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [1] [2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. Genes are turned on and off in different patterns during development to make a brain cell look and act different from a liver cell or a muscle cell, for example. Studying mutant organisms. This will be expanded in the future to include other types of GenBank submissions. About 5% to 10% of breast and 10% to 15% of ovarian cancers are hereditary. Restriction enzymes, or restriction endonucleases, are enzymes made by bacteria. Dr. The human genome is thought to harbor 50,000 to 100,000 genes, of which about half have been sampled to date in the form of expressed sequence tags. Gene Back is a Korean-American film composer and multi-instrumentalist. For example, genes are why one child has blonde hair like their mother, while their sibling has brown hair like their father. nih. 1 17. This is known as the Hardy-Weinberg law. A scanning electron micrograph of a human embryonic. But this isn't completely true. The paired chromosomes are numbered from 1 to 22 according to size. The beginning is the promoter region, the series of nucleotides that is recognized by the enzyme that triggers the transcription of DNA to RNA. ”. To produce this enzyme, the next. at HKUST. Background Eukaryotic genomes undergo pervasive transcription, leading to the production of many types of stable and unstable RNAs. Composer: Cowboys. Genome engineering has a rich history which, when outlined in order, shows an industry determined to aid humanity through the study of genetics. Three years ago in the journal Nature, a vast international research team led in part by Harvard geneticist David Reich shined a torchlight on one of prehistoric Britain’s murkier. A haul of genes that underpin the diversity of human hair has emerged from a major study into our follicular foundations. These laws faced a few controversies initially but when Mendel’s theories got integrated with the chromosome theory of inheritance, they soon became the heart of classical genetics. Higher activities of the UPS appear to retard aging effects [ 13, 14 ]. CRISPR Timeline. We would like to show you a description here but the site won’t allow us. Genetic engineering is the use of molecular biology technology to modify DNA sequence (s) in genomes, using a variety of approaches. Cloning Fact Sheet. 18 The student is able to describe the connection between the regulation of gene expression and observed differences between different kinds of organisms. DNA holds the instructions for building the proteins that carry out a variety of functions in a cell. The phrase is a carefully crafted attempt to distinguish the new, high-precision gene-editing techniques like CRISPR from earlier agricultural biotech, where foreign DNA (transgenes) were added to. Linebacker coach Chris Partridge has been abruptly fired. Unlock your family history in the largest database of last names. In total, we screened 35,175 supplementary Excel files, finding 7467 gene lists attached to 3597 published papers. Class II Transposons. Better health through promotion, protection & prevention. It is most common in individuals homozygous for a recessive allele on chromosome 16. Eukaryotic gene expression begins with control of access to the DNA. 2. Definition. Unlike prokaryotic cells, eukaryotic cells can regulate gene expression at many different levels. A: CRISPRs were first discovered in archaea (and later in bacteria) by Francisco Mojica, a scientist at the University of Alicante in Spain. Scientists hope to alter cowpea seedlings so the crop can reproduce clonally. Transcription is not restricted to regions with annotated gene features but includes almost any genomic context. 1 16. C. 1 Replacement Therapy. He is a visiting scholar at the Whitehead Institute of MIT where he is interested in harnessing iPSC technology and genome and epigenome editing approaches to establish disease relevant models that are genetically accurate for neurological disorders. Groups of transcription factor binding sites called enhancers and silencers can turn a gene on/off in specific parts of the body. The first American composer to have been selected as a British Academy of Film and Television Arts (BAFTA) Breakthrough talent, his scores include critically acclaimed feature films "Cowboys" (dir. As Director of Communication for Bungoma County, I developed and implemented effective knowledge management, information sharing systems and communication strategy that addressed the information needs of different categories of stakeholders. Every organism has a unique body pattern. Dawkins uses the term "selfish gene" as a way of expressing the gene-centred view of evolution (as opposed to the views focused on the organism and. Video by Thecowboy4411@Youtube I`m back in the saddle again Out where a friend is a friend Where the longhorn cattle feed On the lowly gy. So, there are usually 40% active female genes and 60% active male genes. Transcription begins with the opening and unwinding of a small portion of the DNA double helix to expose the bases on each DNA strand. Each gene has three regions, all essential for successful functioning. From conceptualizing the double helix to CRISPR edits, this industry has demonstrated a commitment to game-changing discoveries, all while adhering to a careful set of ethics and regulations. On June 13, the Supreme Court gave its long-awaited answer—a unanimous “no. All the cells of one organisms share the genome. The Food and Drug Administration has cleared Pfizer to resume dosing patients with an experimental hemophilia gene therapy that was put on hold last year because of the risk of dangerous blood clots, the company announced Tuesday.