Consanguinity

Last updated
One legal definition of degrees of consanguinity. The number next to each box in the table indicates the degree of relationship relative to the given person. Table of Consanguinity showing degrees of relationship.svg
One legal definition of degrees of consanguinity. The number next to each box in the table indicates the degree of relationship relative to the given person.

Consanguinity (from Latin consanguinitas 'blood relationship') is the characteristic of having a kinship with a relative who is descended from a common ancestor.

Contents

Many jurisdictions have laws prohibiting people who are related by blood from marrying or having sexual relations with each other. The degree of consanguinity that gives rise to this prohibition varies from place to place. [2] On the other hand, around 20% of the global population lives in areas where consanguinous marriages are preferred. [3] The degree of relationships are also used to determine heirs of an estate according to statutes that govern intestate succession, which also vary from jurisdiction to jurisdiction. [4] In some communities and time periods, cousin marriage is allowed or even encouraged; in others, it is taboo, and considered to be incest.

The degree of relative consanguinity can be illustrated with a consanguinity table in which each level of lineal consanguinity ( generation or meiosis ) appears as a row, and individuals with a collaterally consanguineous relationship share the same row. [5] The Knot System is a numerical notation that describes consanguinity using the Ahnentafel numbers of shared ancestors. [6]

Consanguinity of the kings of France as shown in Arbor genealogiae regum Francorum (Bernard Gui, early 14th century) Bernard Gui BNF lat4975.jpg
Consanguinity of the kings of France as shown in Arbor genealogiae regum Francorum (Bernard Gui, early 14th century)

Modern secular law

The degree of kinship between two people may give rise to several legal issues. Some laws prohibit sexual relations between closely related people, referred to as incestuous. Laws may also bar marriage between closely related people, which are almost universally prohibited to the second degree of consanguinity.[ citation needed ] Some jurisdictions forbid marriage between first cousins, while others do not. Marriage with aunts and uncles (avunculate marriage) is legal in several countries. [7] [8]

Consanguinity is also relevant to inheritance, particularly with regard to intestate succession. In general, laws tend to favor inheritance by persons closely related to the deceased. Some jurisdictions ban citizens from service on a jury on the basis of consanguinity as well as affinity with persons involved in the case. [9] In many countries, laws prohibiting nepotism ban employment of, or certain kinds of contracts with, the near relations of public officers or employees.[ citation needed ]

Religious and traditional law

Judaism

Christianity

Under Roman civil law, which the early canon law of the Catholic Church followed, couples were forbidden to marry if they were within four degrees of consanguinity. [10] Around the ninth century the church raised the number of prohibited degrees to seven and changed the method by which they were calculated; instead of the former Roman practice of counting each generational link up to the common ancestor and then down again to the proposed spouse, the new method computed consanguinity only by counting back the number of generations to the common ancestor. [10] Intermarriage was now prohibited to anyone more closely related than seventh cousins, which meant that in particular the nobility struggled to find partners to marry, the pool of non-related prospective spouses having become substantially smaller. They had to either defy the church's position or look elsewhere for eligible marriage candidates. [10] In the Roman Catholic Church, unknowingly marrying a closely consanguineous blood relative was grounds for a declaration of nullity, but during the eleventh and twelfth centuries dispensations were granted with increasing frequency due to the thousands of persons encompassed in the prohibition at seven degrees and the hardships this posed for finding potential spouses. [11]

In 1215, the Fourth Lateran Council made what they believed was a necessary change to canon law reducing the number of prohibited degrees of consanguinity from seven back to four, but retaining the later method of calculating degrees. [12] [13] After 1215, the general rule was that fourth cousins could marry without dispensation, greatly reducing the need for dispensations. [11] In fourteenth century England, for example, papal dispensations for annulments due to consanguinity (and affinity) were relatively few. [14]

The ban on marriage to minor degrees of relationship imposed by the Roman Catholic Church was met with heavy criticism in the Croatian society in the 11th century, which led to a schism in the Croatian church. [15]

Among the Christian Habesha highlanders of Ethiopia and Eritrea (the predominantly orthodox Christian Amhara and Tigray-Tigrinya), it is a tradition to be able to recount one's paternal ancestors at least seven generations away starting from early childhood, because "those with a common patrilineal ancestor less than seven generations away are considered 'brother and sister' and may not marry." The rule is less strict on the mother's side, where the limit is about four generations back, but still determined patrilinearly. This rule does not apply to Muslims or other ethnic groups. [16]

Islam

The Quran at 4:22–24 states. "Forbidden to you in marriage are: your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters." [17] Therefore, the list of forbidden marriage partners, as read in the Qur'an, Surah 4:23, does not include first cousins. [18] Muhammad himself married his first cousin Zaynab bint Jahsh. [19] [ better source needed ]

Financial incentives to discourage consanguineous marriages exist in some countries: mandatory premarital screening for inherited blood disorders has existed in the UAE since 2004 and in Qatar since 2009, whereby couples with positive results will not receive their marriage grant. [20]

Genetic definitions

Average DNA shared between relatives [21]
RelationshipAverage DNA
shared %
self100%
parent / child50%
sibling50%
half-sibling25%
grandparent / grandchild25%
aunt / uncle / niece / nephew25%
half-aunt / half-uncle / half-niece / half-nephew12.5%
first cousin12.5%
half-first cousin6.25%
double-first cousin25%
great-grandparent / great-grandchild12.5%
grandaunt / granduncle / grandniece / grandnephew12.5%
first cousin once removed6.25%
second cousin3.125%
A simplistic depiction of genetic relatedness after n generations as a 2 progression Gene-distribution.png
A simplistic depiction of genetic relatedness after n generations as a 2 progression
Diagram of common family relationships, where the area of each colored circle is scaled according to the coefficient of relatedness. All relatives of the same relatedness are included together in one of the gray ellipses. Legal degrees of relationship can be found by counting the number of solid-line connections between the self and a relative. Coefficient of relatedness.png
Diagram of common family relationships, where the area of each colored circle is scaled according to the coefficient of relatedness. All relatives of the same relatedness are included together in one of the gray ellipses. Legal degrees of relationship can be found by counting the number of solid-line connections between the self and a relative.

Genetically, consanguinity derives from the reduction in variation due to meiosis that occurs because of the smaller number of near ancestors. Since all humans share between 99.6% and 99.9% of their genome, [22] consanguinity only affects a very small part of the sequence. If two siblings have a child, the child has only two rather than four grandparents. In these circumstances, the probability is increased that the child will inherit two copies of a harmful recessive gene (allele) (rather than only one, which is less likely to have harmful effects).

Genetic consanguinity is expressed as defined in 1922 by Wright [23] with the coefficient of relationship r, where r is defined as the fraction of homozygous due to the consanguinity under discussion. Thus, a parent and child pair has a value of r=0.5 (sharing 50% of DNA), siblings have a value of r=0.5, a parent's sibling has r=0.25 (25% of DNA), and first cousins have r=0.125 (12.5% of DNA). These are often expressed in terms of a percentage of shared DNA but can be also popularly referred to as % of genes although that terminology is technically incorrect.

As a working definition, unions contracted between persons biologically related as second cousins or closer (r ≥ 0.03125) are categorized as consanguineous. This arbitrary limit has been chosen because the genetic influence in marriages between couples related to a lesser degree would usually be expected to differ only slightly from that observed in the general population. Globally it is estimated that at least 8.5% of children have consanguineous parents. [24]

In clinical genetics, consanguinity is defined as a union between two individuals who are related as second cousins or closer, with the inbreeding coefficient (F) equal or higher than 0.0156, where (F) represents the proportion of genetic loci at which the child of a consanguineous couple might inherit identical gene copies from both parents. [25]

It is common to identify one's first- and second-degree cousins, and sometimes third-degree cousins. It is seldom possible to identify fourth-degree cousins, since few people can trace their full family tree back more than four generations. (Nor is it considered important, since fourth cousins tend to be genetically no more similar to each other than they are to any other individual from the same region.) [26]

Epidemiology, rates of occurrence

Cultural factors in favor

Reasons favoring consanguinous marriage have been listed as higher compatibility between husband and wife sharing same social relationships, couples stability, enforcing family solidarity, easier financial negotiations and others. [25] : 187  Consanguinity is a deeply rooted phenomenon in 20% of the world population, mostly in the Middle East, West Asia and North Africa. [25] Globally, the most common form of consanguineous union is between first cousins, in which the spouses share 1⁄8 of their genes inherited from a common ancestor, and so their progeny are homozygous (or more correctly autozygous) at 1⁄16 of all loci (r = 0.0625). [27] Due to variation in geographical and ethnic background and the loci chosen to genotype there is some 2.4% variation expected. [28]

Europe

Historically, some European nobles cited a close degree of consanguinity when they required convenient grounds for divorce, especially in contexts where religious doctrine forbade the voluntary dissolution of an unhappy or childless marriage. [29]

Muslim countries

In the Arab world, the practice of marrying relatives is common. According to the Centre for Arabic Genomic Research, between 40% and 54% of UAE nationals' marriages are between family members, up from 39% in the previous generation. Between 21% and 28% of marriages of UAE nationals were between first cousins. [20] [30] Consanguineous marriage is much less prevalent in Christian Arabs as they do not practice arranged marriages. [31] [32] [33] [34] Additionally, an indult dispensation is required to marriages contracted between first cousins or closer in Arab Christian denominations in communion with the Roman Catholic Church, and the Greek Orthodox Church; there are no similar regulations that apply to first-cousin marriages in the Coptic Orthodox Church. [34]

In Egypt, around 40% of the population marry a cousin. A 1992 survey in Jordan found that 32% were married to a first cousin; a further 17.3% were married to more distant relatives. [35] 67% of marriages in Saudi Arabia are between close relatives as are 54% of all marriages in Kuwait, whereas 18% of all Lebanese were between blood relatives. The incidence of consanguinity was 54.3% among Kuwaiti natives and higher among Bedouins. [36]

It has been estimated that 55% of marriages between Pakistani Muslim immigrants in the United Kingdom are between first cousins, [37] where preferential patrilateral parallel cousin marriage, i.e. a man marrying the daughter of his father's brother, is favored.

Double first cousins are descended from two pairs of siblings, and have the same genetic similarity as half-siblings. In unions between double first cousins, the highest inbreeding coefficients are reached, with an (F) of 0.125, for example among Arabs and uncle-niece marriages in South India.

Quebec

The early days of colonization, particularly from 1660 to 1680, gave French Canadians genetic traits that are still present today, thanks to the isolation and low population of the early colony. This has led to the province having a higher rate of hypercholesterolemia, tyrosinemia, spastic ataxia, intestinal atresia, myotonic dystrophy, etc., in the population than anywhere else in the world. [38]

Genetic disorders

The phenomenon of inbreeding increases the level of homozygotes for autosomal genetic disorders and generally leads to a decreased biological fitness of a population known as inbreeding depression, a major objective in clinical studies. [39] While the risks of inbreeding are well-known, informing minority group families with a tradition of endogamy and changing their behavior is a challenging task for genetic counseling in the health care system. [40] The offspring of consanguineous relationships are at greater risk of certain genetic disorders. Autosomal recessive disorders occur in individuals who are homozygous for a particular recessive gene mutation. [41] This means that they carry two copies (alleles) of the same gene. [41] Except in certain rare circumstances (new mutations or uniparental disomy) both parents of an individual with such a disorder will be carriers of the gene. [41] Such carriers are not affected and will not display any signs that they are carriers, and so may be unaware that they carry the mutated gene. As relatives share a proportion of their genes, it is much more likely that related parents will be carriers of an autosomal recessive gene, and therefore their children are at a higher risk of an autosomal recessive disorder. [42] The extent to which the risk increases depends on the degree of genetic relationship between the parents; so the risk is greater in mating relationships where the parents are close relatives, but for relationships between more distant relatives, such as second cousins, the risk is lower (although still greater than the general population). [43]

Consanguinity in a population increases its susceptibility to infectious pathogens such as tuberculosis and hepatitis but may decrease its susceptibility to malaria and other pathogens. [44]

See also

Related Research Articles

Incest is sex between close relatives, for example a brother or sister or cousins. This typically includes sexual activity between people in consanguinity, and sometimes those related by lineage. It is condemned and considered immoral in most societies, given that it can lead to an increased risk of genetic disorders in children in case of pregnancy from incestuous sex.

<span class="mw-page-title-main">Inbreeding</span> Reproduction by closely related organisms

Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious recessive traits resulting from incestuous sexual relationships and consanguinity. Animals avoid inbreeding only rarely.

An incest taboo is any cultural rule or norm that prohibits sexual relations between certain members of the same family, mainly between individuals related by blood. All known human cultures have norms that exclude certain close relatives from those considered suitable or permissible sexual or marriage partners, making such relationships taboo. However, different norms exist among cultures as to which blood relations are permissible as sexual partners and which are not. Sexual relations between related persons which are subject to the taboo are called incestuous relationships.

Exogamy is the social norm of mating or marrying outside one's social group. The group defines the scope and extent of exogamy, and the rules and enforcement mechanisms that ensure its continuity. One form of exogamy is dual exogamy, in which two groups continually intermarry with each other.

Endogamy is the cultural practice of mating within a specific social group, religious denomination, caste, or ethnic group, rejecting any from outside of the group or belief structure as unsuitable for marriage or other close personal relationships. Its opposite, exogamy, describes the social norm of marriage outside of the group.

The coefficient of relationship is a measure of the degree of consanguinity between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of the coefficient of inbreeding of 1921. The measure is most commonly used in genetics and genealogy. A coefficient of inbreeding can be calculated for an individual, and is typically one-half the coefficient of relationship between the parents.

<span class="mw-page-title-main">Pedigree collapse</span> Concept in genealogy

In genealogy, pedigree collapse describes how reproduction between two individuals who share an ancestor causes the number of distinct ancestors in the family tree of their offspring to be smaller than it could otherwise be. Robert C. Gunderson coined the term; synonyms include implex and the German Ahnenschwund.

<span class="mw-page-title-main">Affinity (Catholic canon law)</span> Concept in impediments to marriage

In Catholic canon law, affinity is an impediment to marriage of a couple due to the relationship which either party has as a result of a kinship relationship created by another marriage or as a result of extramarital intercourse. The relationships that give rise to the impediment have varied over time. Marriages and sexual relations between people in an affinity relationship are regarded as incest.

A cousin is a relative that is the child of a parent's sibling; this is more specifically referred to as a first cousin.

Inbreeding depression is the reduced biological fitness that has the potential to result from inbreeding. The loss of genetic diversity that is seen due to inbreeding, results from small population size. Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. Inbreeding depression is often the result of a population bottleneck. In general, the higher the genetic variation or gene pool within a breeding population, the less likely it is to suffer from inbreeding depression, though inbreeding and outbreeding depression can simultaneously occur.

In law and in cultural anthropology, affinity is the kinship relationship created or that exists between two people as a result of someone's marriage. It is the relationship each party in the marriage has to the family of the other party in the marriage. It does not cover the marital relationship itself. Laws, traditions and customs relating to affinity vary considerably, sometimes ceasing with the death of one of the marriage partners through whom affinity is traced, and sometimes with the divorce of the marriage partners. In addition to kinship by marriage, "affinity" can sometimes also include kinship by adoption or a step relationship.

A cousin marriage is a marriage where the spouses are cousins. The practice was common in earlier times and continues to be common in some societies today, though in some jurisdictions such marriages are prohibited. Worldwide, more than 10% of marriages are between first or second cousins. Cousin marriage is an important topic in anthropology and alliance theory.

Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity.

In law, a prohibited degree of kinship refers to a degree of consanguinity, or sometimes affinity between persons that makes sex or marriage between them illegal.

Laws regarding incest vary considerably between jurisdictions, and depend on the type of sexual activity and the nature of the family relationship of the parties involved, as well as the age and sex of the parties. Besides legal prohibitions, at least some forms of incest are also socially taboo or frowned upon in most cultures around the world.

<span class="mw-page-title-main">Cousin marriage in the Middle East</span>

Cousin marriage is a form of consanguinity. While consanguinity is not unique to the Arab or Islamic world, Arab countries have had "some of the highest rates of consanguineous marriages in the world". The bint 'amm marriage, or marriage with one's father's brother's daughter is especially common, especially in tribal and traditional Muslim communities, where men and women seldom meet potential spouses outside the extended family.

Consanguine marriage is marriage between individuals who are closely related. Though it may involve incest, it implies more than the sexual nature of incest. In a clinical sense, marriage between two family members who are second cousins or closer qualifies as consanguineous marriage. This is based on the gene copies their offspring may receive. Though these unions are still prevalent in some communities, as seen across the Greater Middle East region, many other populations have seen a great decline in intra-family marriages.

An avunculate marriage is a marriage with a parent's sibling or with one's sibling's child—i.e., between an uncle or aunt and their niece or nephew. Such a marriage may occur between biological (consanguine) relatives or between persons related by marriage (affinity). In some countries, avunculate marriages are prohibited by law, while in others marriages between such biological relatives are both legal and common, though now far less common.

Genetic studies on Arabs refers to the analyses of the genetics of ethnic Arab people in the Middle East and North Africa. Arabs are genetically diverse as a result of their intermarriage and mixing with indigenous people of the pre-Islamic Middle East and North Africa following the Arab and Islamic expansion. Genetic ancestry components related to the Arabian Peninsula display an increasing frequency pattern from west to east over North Africa. A similar frequency pattern exist across northeastern Africa with decreasing genetic affinities to groups of the Arabian Peninsula along the Nile river valley across Sudan and the more they go south. This genetic cline of admixture is dated to the time of Arab expansion and immigration to North Africa (Maghreb) and northeast Africa.

Prevention of autosomal recessive disorders is focused on making it less likely that two carriers for the same hereditary disease will have children together.

References

  1. ↑ "19 Texas Administrative Code §100.1113". texreg.sos.state.tx.us. State of Texas. Retrieved 5 May 2022. Many other US states have the same definition.
  2. ↑ O'Sullivan, Kathryn (2019). "Access to marriage: consanguinity and affinity prohibitions in national and international context". Irish Journal of Family Law. 22 (2): 8–12.
  3. ↑ Modell, Bernadette; Darr, Aamra (March 2002). "Science and society: genetic counselling and customary consanguineous marriage". Nature Reviews. Genetics. 3 (3): 225–229. doi:10.1038/nrg754. ISSN   1471-0056. PMID   11972160 . Retrieved 2024-08-09.
  4. ↑ Ritchie, Herbert (1940). "Methods of Intestate Succession". University of Cincinnati Law Review. 14: 508.
  5. ↑ "Table of Consanguinity". Sleepy Hollow Cemetery.
  6. ↑ Højrup, Knud (June 1996). "The Knot System: A Numeric Notation of Relationship". National Genealogical Society Quarterly. 84 (2): 115. ISSN   0027-934X.
  7. ↑ "RCW 26.04.020: Prohibited marriages". app.leg.wa.gov. Retrieved 2021-10-01.
  8. ↑ Farrow, Michael G.; Juberg, Richard C. (1969-07-28). "Genetics and Laws Prohibiting Marriage in the United States". JAMA. 209 (4): 534–538. doi:10.1001/jama.1969.03160170030006. ISSN   0098-7484. PMID   5819418.
  9. ↑ Ohio, for example, bars from juries in civil cases persons within the fourth degree of consanguinity to either party or their counsel (Ohio Revised Code §2313.17 (2012)); and persons within the fifth degree of consanguinity "to the person alleged to be injured or attempted to be injured by the offense charged, or to the person on whose complaint the prosecution was instituted, or to the defendant". Ohio Revised Code §2945.25 (1981).
  10. 1 2 3 Constance Brittain Bouchard (24 November 2010). Those of My Blood: Creating Noble Families in Medieval Francia. University of Pennsylvania Press. p. 40. ISBN   978-0-8122-0140-6.
  11. 1 2 James A. Brundage (15 February 2009). Law, Sex, and Christian Society in Medieval Europe. University of Chicago Press. p. 356. ISBN   978-0-226-07789-5.
  12. ↑ "Fourth Lateran Council: Canon 50. Prohibition of marriage is now perpetually restricted to the fourth degree". 1215. Archived from the original on 2016-08-20.
  13. ↑ John W. Baldwin (28 May 1994). The Language of Sex: Five Voices from Northern France Around 1200. University of Chicago Press. p. 78. ISBN   978-0-226-03613-7.
  14. ↑ R. H. Helmholz (26 March 2007). Marriage Litigation in Medieval England. Cambridge University Press. p. 86. ISBN   978-0-521-03562-0.
  15. ↑ Dvornik, Francis (1970). Byzantine mission among the Slavs. Rutgers University Press. p. 241. ISBN   0813506131.
  16. ↑ Wolbert Smidt, "Genealogy" in Siegbert Uhlig, ed., Encyclopaedia Aethiopica: D-Ha, (Wiesbaden: Harrassowitz Verlag, 2005), p. 743.
  17. ↑ "Surah An-Nisa [4:22–25]". Quran.com. Retrieved 16 June 2018.
  18. ↑ "The Qur'an". Quran Surah An-Nisaa ( Verse 23 )
  19. ↑ "Islam's Women". unknown. n.d.
  20. 1 2 Consanguineous marriage: Should it be discouraged? Archived 2017-10-10 at the Wayback Machine June 2012, MiddleEastHealthMag.com, retrieved 28 Nov 2018
  21. ↑ "Average percent DNA shared between relatives". 23andme. Archived from the original on 2018-05-05. Retrieved 2018-05-06.
  22. ↑ Jorde, Lynn B; Wooding, Stephen P (2004). "Genetic variation, classification and 'race'". Nature Genetics. 36 (11s): S28–S33. doi: 10.1038/ng1435 . PMID   15508000.
  23. ↑ Wright, Sewall (1922). "Coefficients of inbreeding and relationship". American Naturalist . 56 (645): 330–338. doi:10.1086/279872. S2CID   83865141.
  24. ↑ Darr, Aamra (14 October 2010). "Consanguineous Marriage and Inherited Disorders" (PDF). University of Bradford: City of Bradford. Retrieved 31 August 2016.
  25. 1 2 3 Hamamy, H. (2011). "Consanguineous marriages: Preconception consultation in primary health care settings". Journal of Community Genetics. 3 (3): 185–192. doi:10.1007/s12687-011-0072-y. PMC   3419292 . PMID   22109912.
  26. ↑ Davis, Erin Cline (10 October 2008). "Understanding Genetics: How much genetic similarity is considered baseline relatedness?". Ask a Geneticist. thetech.org. Retrieved 28 November 2023.
  27. ↑ Bittles, A H (2001). "A Background Summary of Consanguineous Marriage" (PDF). Centre for Human Genetics Edith Cowan University, Perth, Australia. Archived from the original (PDF) on 27 September 2018. Retrieved 31 August 2016.
  28. ↑ Rehder; et al. (2013). "Documenting suspected consanguinity guidelines". Genet Med. 15 (2): 150–152. doi: 10.1038/gim.2012.169 . PMID   23328890.
  29. ↑ James A. Brundage, Law, Sex, and Christian Society in Medieval Europe (Chicago: University of Chicago Press, 1995), p. 193
  30. ↑ Bener A, Dafeeah EE, Samson N (2012). "Does consanguinity increase the risk of schizophrenia? Study based on primary health care centre visits". Ment Health Fam Med. 9 (4): 241–8. PMC   3721918 . PMID   24294299.
  31. ↑ Tadmouri, Ghazi O; Nair, Pratibha; Obeid, Tasneem; Al Ali, Mahmoud T; Al Khaja, Najib; Hamamy, Hanan A (2009-10-08). "Consanguinity and reproductive health among Arabs". Reproductive Health. 6: 17. doi: 10.1186/1742-4755-6-17 . ISSN   1742-4755. PMC   2765422 . PMID   19811666.
  32. ↑ Vardi-Saliternik, R.; Friedlander, Y.; Cohen, T. (Summer 2002). "Consanguinity in a population sample of Israeli Muslim Arabs, Christian Arabs and Druze". Annals of Human Biology. 29 (4): 422–431. doi:10.1080/03014460110100928. ISSN   0301-4460. PMID   12160475. S2CID   28335793.
  33. ↑ Freundlich, E.; Hino, N. (November 1984). "Consanguineous marriage among rural Arabs in Israel". Israel Journal of Medical Sciences. 20 (11): 1035–1038. ISSN   0021-2180. PMID   6511329.
  34. 1 2 Bittles, Alan H.; Hamamy, Hanan A. (2010), Teebi, Ahmad S. (ed.), "Endogamy and Consanguineous Marriage in Arab Populations", Genetic Disorders Among Arab Populations, Springer Berlin Heidelberg, pp. 85–108, doi:10.1007/978-3-642-05080-0_4, ISBN   9783642050800
  35. ↑ Consanguineous marriage: Keeping it in the family. Economist, 27 February 2016.
  36. ↑ Keith Garbutt Inbreeding and genetic disorder among Arab population. Archived 2017-12-20 at the Wayback Machine WVU unpublished Paper
  37. ↑ "Marriage between cousins increases risks to children". medicinechest.co.uk. n.d. Archived from the original on 14 April 2019. Retrieved 28 November 2018.
  38. ↑ Portrait de famille avec gènes by Mathieu-Robert Sauvé, Retrieved August 2021.
  39. ↑ Fareed M, Afzal M (2014). "Evidence of inbreeding depression on height, weight, and body mass index: a population-based child cohort study". Am. J. Hum. Biol. 26 (6): 784–95. doi:10.1002/ajhb.22599. PMID   25130378. S2CID   6086127.
  40. ↑ Staal, J (2017). "Applied Cultural and Social Studies are Needed for a Sustainable Reduction of Genetic Disease Incidence". European Journal of Sociology and Anthropology. 2 (1): 1–10. doi: 10.20897/ejsa.201701 . hdl: 1854/LU-8526232 .
  41. 1 2 3 William J Marshall, Ph. D.; S K Bangert, Clinical biochemistry : metabolic and clinical aspects (Edinburgh; New York: Churchill Livingstone/Elsevier, 2008), p. 920
  42. ↑ Benjamin Pierce, Genetics: A Conceptual Approach (New York: W.H. Freeman, 2012), p. 138
  43. ↑ Kingston H M, "ABC of Clinical Genetics", 3rd Edition (London: BMJ Books, 2002), Page 7, ISBN   0-7279-1627-0
  44. ↑ Lyons EJ, Frodsham AJ, Zhang L, Hill AV, Amos W (2009). "Consanguinity and susceptibility to infectious diseases in humans". Biol Lett. 5 (4): 574–6. doi:10.1098/rsbl.2009.0133. PMC   2684220 . PMID   19324620.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.