Xq28 is a chromosome band and genetic marker situated at the tip of the X chromosome which has been studied since at least 1980. The band contains three distinct regions, totaling about 8 Mbp of genetic information. The marker came to the public eye in 1993 when studies by Dean Hamer and others indicated a link between the Xq28 marker and male sexual orientation .
47-477: The 1993 study by Hamer et al. examined 114 families of gay men in the United States and found increased rates of homosexuality among maternal uncles and cousins, but not among paternal relatives. This pattern of inheritance suggested that there might be linked genes on the X chromosome , since males always inherit their copy of the X chromosome from their mothers. Polymorphisms of genetic markers of
94-483: A chronological cluster map. These cluster maps show the origin of cases and the time in which those cases arose. This gives a much clearer picture of transmission dynamics and allows for better control and prevention of transmission. All of these different forms of genotyping are used together to detect TB, prevent its spread and trace the origin of infections. This has helped to reduce the number of TB cases. Many types of genotyping are used in agriculture . One type that
141-474: A large, comprehensive multi-center genetic linkage study of male sexual orientation conducted by several independent groups of researchers. Analysis of 409 pairs of gay brothers with over 300,000 single-nucleotide polymorphism markers confirmed the Xq28 linkage by two-point and multipoint LOD score mapping. Significant linkage was also detected in the pericentromeric region of chromosome 8, overlapping with one of
188-434: A person to develop a disease, but disease development is not guaranteed in most cases, which can cause psychological damage. Discrimination can arise from various genetic markers identified by genotyping, such as athletic advantages or disadvantages in professional sports or risk of disease development later in life. Much of the ethical concerns surrounding genotyping arise from information availability, as in who can access
235-460: A potent anti-HIV peptide, significant protection against viral infection was provided in a durable and obtainable fashion for up to one month. The methodology was shown to be applicable to both rectal and vaginal use and is in the initial stages of preclinical testing. Hamer turned to documentary filmmaking to address complex scientific and social issues often overlooked by the mainstream media. In 2005, he and partner Joe Wilson formed Qwaves with
282-467: A single question to the subject). They also lacked criteria "to select appropriate families for the study of a putative X-linked locus" — as they did not select families based on the presence of maternal transmission of homosexuality, the Xq28 contribution to male sexual orientation may have been hidden. In addition, the meta-analysis revealed that the family pedigree data of Rice et al. (1999), in contrast to
329-762: A tiny fraction of the human genome . When genotyping transgenic organisms, a single genomic region may be all that needs to be examined to determine the genotype. A single PCR assay is typically enough to genotype a transgenic mouse ; the mouse is the mammalian model of choice for much of medical research today. The ethical concerns of genotyping humans have been a topic of discussion. The rise of genotyping technologies will make it possible to screen large populations of people for genetic diseases and predispositions for disease. The benefits of population wide genotyping have been contended by ethical concerns on consent and general benefit of wide span screening. Genotyping identifies mutations that increase susceptibility of
376-408: Is important in research of genes and gene variants associated with disease. Due to current technological limitations, almost all genotyping is partial. That is, only a small fraction of an individual's genotype is determined, such as with (epi)GBS ( Genotyping by sequencing ) or RADseq . New mass-sequencing technologies promise to provide whole-genome genotyping (or whole genome sequencing ) in
423-505: Is preferentially transmitted through the maternal side and is genetically linked to the Xq28 region. A follow-up study, Hu et al. (1995), conducted by the Hamer lab in collaboration with two groups of statistical experts in 1995, corroborated the original results for males with homosexual brothers sharing Xq28 at significantly elevated rates. This study also included heterosexual brothers, who showed significantly less than expected sharing of
470-464: Is the process of determining differences in the genetic make-up ( genotype ) of an individual by examining the individual's DNA sequence using biological assays and comparing it to another individual's sequence or a reference sequence. It reveals the alleles an individual has inherited from their parents. Traditionally genotyping is the use of DNA sequences to define biological populations by use of molecular tools. It does not usually involve defining
517-434: Is used is genotyping by sequencing because it aids agriculture with crop breeding. For this purpose, single nucleotide polymorphisms (SNPs) are used as markers and RNA sequencing is used to look at gene expression in crops. The knowledge gained from this type of genotyping allows for selective breeding of crops in ways which benefit agriculture. In the case of alfalfa, the cell wall was improved through selective breeding that
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#1732801355211564-722: The MECP2 and IRAK1 genes within Xq28 have been associated with phenotypes including anxiety and autism in mice . Dean Hamer Dean Hamer ( / ˈ h eɪ m ər / ; born May 29, 1951) is an American geneticist , author , and filmmaker . He is known for his research on the role of genetics in sexual orientation and for a series of popular books and films that have changed scientific and public understandings and perceptions of human sexuality and gender. Born in Montclair, New Jersey , Hamer obtained his BA at Trinity College , CT , and his PhD from Harvard Medical School . He
611-852: The Mellon Foundation , the project aims to document and memorialize gender and sexual diversity across the multicultural landscape of the Hawaiian islands. Hamer is a frequent guest on TV documentaries and news shows including Good Morning America , Nightline and The Oprah Winfrey Show . He is featured in the Barbara Walters ' special Heaven and Bill Maher documentary Religulous , and has been profiled in Time magazine. According to Google Scholar , Hamer's works have been cited over 27,000 times and he has an h-index of 72 as of August 2020. Genotyping Genotyping
658-439: The genotype of an individual in various contexts. Genotyping is used in the medical field to identify and control the spread of tuberculosis (TB). Originally, genotyping was only used to confirm outbreaks of tuberculosis; but with the evolution of genotyping technology it is now able to do far more. Advances in genotyping technology led to the realization that many cases of tuberculosis, including infected individuals living in
705-585: The Kapaemahu monument in Waikiki. The team's most recent film is Aikane , an animated short based on the Hawaiian term for intimate friends of the same sex. It won two Academy Award-qualifying film festival awards and was nationally distributed by Conde Nast on the Them platform. In 2024, Hamer initiated a multimedia community engagement and storytelling effort on the "Queer Histories of Hawai'i." Funded by
752-435: The X chromosome were analyzed for 40 families to see if a specific marker was shared by a disproportionate amount of brothers who were both gay. The results showed that among gay brothers, the concordance rate for markers from the Xq28 region were significantly greater than expected for random Mendelian segregation, indicating that a link did exist in that small sample. It was concluded that at least one form of male homosexuality
799-488: The X-chromosome, they found no excess of signal (and no individual genome-wide significant variants) on Xq28 or the rest of the X chromosome. Xq28 is a large, complex, and gene-dense region. Among its various genes are the 12 genes of the melanoma-associated antigen (MAGE) family, of which MAGEA11 has been identified as a coregulator for the androgen receptor . Mutations involving the production of extra copies of
846-449: The Xq28 linkage to homosexuality by two-point and multipoint (MERLIN) LOD score mapping. Significant linkage was also detected in the region near the centromere of chromosome 8 , overlapping with one of the regions detected in a previous genomewide linkage study by the Hamer lab. The authors concluded that "our findings, taken in context with previous work, suggest that genetic variation in each of these regions contributes to development of
893-630: The Xq28 linkage. A meta-analysis of all data available at that time (i.e., Hamer et al. (1993), Hu et al. (1995), Rice et al. (1999), and the unpublished 1998 study by Sanders et al. indicated that Xq28 has a significant but not exclusive role in male sexual orientation. The authors of the meta-analysis (which included three authors of the Rice et al. study, Rice, Risch and Ebers) presented several methodological reasons due to which Rice et al. (1999) may have been unable to detect statistically significant linkage between Xq28 and male sexual orientation:
940-408: The Xq28 region, as expected for a genetic locus that in one form is associated with same-sex attraction and in another form is associated with opposite-sex attraction. In this study no link to Xq28 was found among homosexual females, indicating a different genetic pathway as for most sex-specific phenotypes. Hamer's findings were highlighted in scientific journals including Science , Nature and
987-471: The chromosomal location of maximum sharing was locus DXS1108 and both reported similar degrees of allele sharing (66% versus 67%). The second study by Rice et al. in 1999 studied 52 pairs of Canadian gay brothers and found no statistically significant linkage in alleles and haplotypes . Consequently, they concluded against the possibility of any gene in the Xq28 region having a large genetic influence on male sexual orientation (though they could not rule out
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#17328013552111034-483: The data ended in December 1996. It determined that Hamer had not committed any scientific misconduct in his study. Two further studies in the 1990s gave mixed results. One was an X chromosome linkage analysis of 54 pairs of gay brothers carried out by the independent research group of Sanders et al. in 1998. The results of the study were indistinguishable from the results of the study by Hu et al. : both reported that
1081-437: The families genotyped by Rice et al. were non-representative as they had an excess of paternal instead of maternal gay relatives thus obscuring the display of any X-chromosome linkage; the statistical power of their sample was insufficient to adequately detect linkage and they lacked definite criteria for what constituted as homosexuality (the researchers depended on their own judgement and sometimes based their judgement on
1128-564: The first eukaryotic gene regulatory systems to be understood at the molecular level and a useful method for regulating therapeutic protein production. In the 1990s Hamer began studies on the genetics of human behavior , which led to the first molecular evidence for genes that influence human sexual orientation . His research group's first paper, published in Science in 1993, reported that the maternal but not paternal male relatives of gay men had increased rates of same-sex orientation, suggesting
1175-472: The first method for introducing new genes into animal cells using SV40 vectors while a graduate student at Harvard Medical School . This approach was used to produce a variety of biomedical products including human growth hormone and a vaccine for Hepatitis B , resulting in 4 US patents . At NIH, Hamerʻs lab initially focused on the metallothionein gene system. They elucidated the mechanism of induction of yeast metallothionein by copper ions, one of
1222-483: The first of many to come. Hamer's findings provoked extensive public reaction, often based on misunderstanding of the science, which led to his interest in explaining the data to a wide audience through a book written in collaboration with a journalist. Social science surveys have shown that research on the origins of sexual orientation has a strong positive influence on people's attitudes of acceptance and inclusion of LGBT people. Hamer and colleagues also investigated
1269-568: The future. Genotyping applies to a broad range of individuals, including microorganisms. For example, viruses and bacteria can be genotyped. Genotyping in this context may help in controlling the spreading of pathogens, by tracing the origin of outbreaks. This area is often referred to as molecular epidemiology or forensic microbiology . Humans can also be genotyped. For example, when testing fatherhood or motherhood, scientists typically only need to examine 10 or 20 genomic regions (like single-nucleotide polymorphism (SNPs)), which represent
1316-438: The genes of an individual. Current methods of genotyping include restriction fragment length polymorphism identification (RFLPI) of genomic DNA, random amplified polymorphic detection (RAPD) of genomic DNA, amplified fragment length polymorphism detection (AFLPD), polymerase chain reaction (PCR), DNA sequencing , allele specific oligonucleotide (ASO) probes, and hybridization to DNA microarrays or beads. Genotyping
1363-442: The genetic roots of anxiety and found that a promoter region polymorphism in the gene for the serotonin transporter, which is the target of antidepressant drugs such as Prozac , is associated with mood and personality. This finding has been extensively replicated and extended and its activity has been confirmed by direct brain imaging studies. In 2004, Hamer used data from ongoing behavioral genetics studies in his lab to explore
1410-412: The genotyping data, seemed to support X chromosome linkage for homosexuality. In 2012, a large, comprehensive genome-wide linkage study of male sexual orientation was conducted by several independent groups of researchers. The study population included 409 independent pairs of gay brothers from 384 families, who were analyzed with over 300,000 single-nucleotide polymorphism markers. The study confirmed
1457-711: The healing arts from Tahiti to Hawaii. It premiered and won the Special Jury Prize at the Tribeca Film Festival and was shortlisted for an Oscar as Best Animated Short Film at the 93rd Academy Awards . The animated film was followed by a children's book published by Kokila, a PBS feature documentary, a multimedia exhibition at the Bishop Museum, permanent display at the Hawai'i Convention center, and inclusion in new interpretative signage at
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1504-592: The important psychological trait of male sexual orientation." It was the largest study of the genetic basis of homosexuality to date and was published online in November 2014. In August 2019, a genome-wide association study of 493,001 individuals concluded that hundreds or thousands of genetic variants underlie homosexual behavior in both sexes, with 5 variants in particular being significantly associated. They stated that in contrast to linkage studies that found substantial association of sexual orientation with variants on
1551-765: The mission of producing "insightful and provocative films that emanate from the voices of those on the outside and compel us to question and to act." Their short films won multiple awards including winner of the PBS Independent Lens Shorts Festival and Seeds of Tolerance Award. Out in the Silence , the first feature film from Qwaves, documented the controversy that was ignited by Hamer and Wilson's wedding announcement in Wilson's conservative small hometown in Pennsylvania The film
1598-416: The possibility of a gene in this region having a small influence). Rice et al. also asserted that their results do not exclude the possibility of finding male homosexuality genes elsewhere in the genome . Hamer criticized the study for not selecting families for their study population based on maternal transmission as selecting only families that show an excess of maternal gay relatives is necessary to detect
1645-494: The possibility of genetic influences on spirituality. In The God Gene: How Faith is Hardwired into our Genes, he proposed that a quantitative measure of self-transcendence is partially heritable and may be correlated to a specific gene, VMAT2 , involved in monamine metabolism. Hamer's speculations on the possible role of genetics in religious experience were featured in a cover story in Time magazine. Hamer's lab developed several biotechnological strategies to treat and reduce
1692-405: The possibility of sex-linked transmission in a portion of the population. A genetic linkage analysis of DNA samples from these families showed that gay brothers had an increased probability of sharing polymorphic markers on the subtelomeric region of the long arm of the X chromosome , Xq28 , providing statistically significant evidence for linkage to the sexual orientation phenotype. This finding
1739-551: The regions detected in the Hamer lab's previous genomewide study. The authors concluded that "our findings, taken in context with previous work, suggest that genetic variation in each of these regions contributes to development of the important psychological trait of male sexual orientation." In August 2019, a genome-wide association study of 493,001 individuals concluded that hundreds or thousands of genetic variants underlie same-sex sexual behavior in both sexes, but in contrast to linkage studies they found no excess of signal on Xq28 or
1786-488: The rest of the X chromosome. This study was questioned on account of its reliance on a dichotomous ever/never measure that lumped together predominantly heterosexual, bisexual and homosexual individuals, including those who only experimented once with a same-sex partner, possibly resulting in misleading associations to personality traits. Hamer said that the findings of the 2019 study do not reveal any biological pathways for sexual orientation, but stated he hoped it would be
1833-536: The same household, were not actually linked. This caused the formation of universal genotyping in an attempt to understand transmission dynamics. Universal genotyping revealed complex transmission dynamics based on things like socio-epidemiological factors. This led to the use of polymerase chain reactions (PCR) which allowed for faster detection of tuberculosis. This rapid detection method is used to prevent TB. The addition of whole genome sequencing (WGS) allowed for identification of strains of TB which could then be put in
1880-542: The topic of a mini-symposium in Scientific American . In June 1994, an article in the Chicago Tribune by John Crewdson stated that an anonymous junior researcher in Hamer's laboratory alleged that Hamer selectively presented the data in his 1993 paper in the journal Science . The junior researcher had assisted in the gene mapping in Hamer's 1993 study. Shortly after voicing her questions, she
1927-427: The transmission of HIV/AIDS. As a means to reduce the latent pools of virus responsible for viral persistence, they discovered novel chemical agent to induce integrated virus, and molecularly-engineered immunotoxins to destroy the infected cells. They also collaborated with Osel, Inc. on a novel "live microbial microbicide " approach to HIV/AIDS prevention. By genetically engineering normal vaginal bacteria to produce
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1974-716: Was an independent researcher at the National Institutes of Health for 35 years, where he was the Chief of Gene Structure and Regulation Section at the U.S. National Cancer Institute ; upon retirement in 2011 he was designated Scientist Emeritus . Hamer has won numerous awards including the Trinity College Thompson History Prize, Maryland Distinguished Young Scientist Award, Ariens Kappers Award for Neurobiology, New York Times book-of-the year author, and an Emmy Award. Hamer invented
2021-515: Was followed in 2019 by The Rogers , about transgender men in Samoa. These films became part of a campaign to decriminalize same-sex relationships across the Pacific. Hamer, Wilson and Wong-Kalu continued their collaboration in 2020 with the animated short film Kapaemahu , based on the hidden history of four stones on Waikiki Beach placed there as a tribute to four legendary mahu who first brought
2068-478: Was replicated in two other studies in the United States whereas a study in Canada found contrary results; meta-analysis of all data available at that time suggested that Xq28 has a significant but not exclusive effect. Subsequently, a genomewide scan by Hamerʻs group revealed additional regions on autosomes that were moderately linked to male sexual orientation. Hamer's results were robustly replicated in 2012 in
2115-467: Was summarily dismissed from her post-doctoral fellowship in Hamer's lab; who dismissed her could not be determined. Later, she was given another position in a different lab. Hamer stated that Crewdson's article was "seriously in error" and denied the allegations made against him. An official inquiry launched by the Office of Research Integrity (ORI) to investigate the allegations of selective presentation of
2162-757: Was supported by ITVS , Pacific Islanders in Communications and the Ford Foundation and won the GLAAD Media Award for Outstanding Documentary and the Independent Lens Audience Award on PBS In 2017, Hamer and Wilson, with Hinaleimoana Wong-Kalu as producer, released Leitis in Waiting a nd Lady Eva , which documented the lives of transgender women in the conservative South Pacific Kingdom of Tonga. This
2209-803: Was supported by the Sundance Documentary Film Program and won an Emmy Award for achievement in documentary. The Out in the Silence Youth Activism Award was initiated in 2011 to highlight the contributions of young people to achieving respect, inclusion and equality for lesbian, gay, bisexual and transgender people. In 2011, Hamer and Wilson moved to Hawaiʻi to begin a series of films about Pacific Islander lives and voices and long tradition of acceptance of sexual and gender minorities. Their feature documentary Kumu Hina , about transgender native Hawaiian teacher and cultural icon Hinaleimoana Wong-Kalu ,
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