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  <xsd:element id="dawn_MaketValueOfCommonStockHeldByNonAffiliateStockholders" name="MaketValueOfCommonStockHeldByNonAffiliateStockholders" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_CashEquivalentsUnrealizedLosses" name="CashEquivalentsUnrealizedLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionMoreThan12MonthsAccumulatedLoss" name="AvailableForSaleSecuritiesContinuousUnrealizedLossPositionMoreThan12MonthsAccumulatedLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_FounderOneMember" name="FounderOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AvailableForSaleMarketableSecurities" name="AvailableForSaleMarketableSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_TwoThousandAndTwentyOneEmployeeStockPurchasePlanMember" name="TwoThousandAndTwentyOneEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_TemporaryEquityIssuePricePerShare" name="TemporaryEquityIssuePricePerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="dawn_TwoThousandTwentyOneEmployeeStockPurchasePlanMember" name="TwoThousandTwentyOneEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_CommonStockIssuedPursuantToFollowOnOfferingNetOfIssuanceCostsAmount" name="CommonStockIssuedPursuantToFollowOnOfferingNetOfIssuanceCostsAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_MilestoneAchievedMember" name="MilestoneAchievedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AccruedResearchAndDevelopmentExpenses" name="AccruedResearchAndDevelopmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_CashEquivalentsUnrealizedGains" name="CashEquivalentsUnrealizedGains" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_UpfrontOfCashPayment" name="UpfrontOfCashPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_IncrementalSharesReservedForFutureIssuanceMember" name="IncrementalSharesReservedForFutureIssuanceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_EmergingGrowthCompanyStatusPolicyTextBlock" name="EmergingGrowthCompanyStatusPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_UnvestedPerformanceStockUnitsMember" name="UnvestedPerformanceStockUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AccountingPoliciesTable" name="AccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AvailableForSaleSecuritieContinuousUnrealizedLossPositionAccumulatedLoss" name="AvailableForSaleSecuritieContinuousUnrealizedLossPositionAccumulatedLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_FirstAnniversaryMember" name="FirstAnniversaryMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_DeferredSharesOutstanding" name="DeferredSharesOutstanding" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="dawn_DepositsAndOtherLongtermAssetsNonCurrent" name="DepositsAndOtherLongtermAssetsNonCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_GrossProceedsMember" name="GrossProceedsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_BrisbaneCaliforniaMember" name="BrisbaneCaliforniaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_ShareBasedCompensationByShareBasedPaymentAwardConversionOfIncentiveShareIntoRestrictedStockWeightedAverageGrantDateFairValue" name="ShareBasedCompensationByShareBasedPaymentAwardConversionOfIncentiveShareIntoRestrictedStockWeightedAverageGrantDateFairValue" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_RedeemableNonControllingInterestTextBlock" name="RedeemableNonControllingInterestTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_MilestonePaymentsNotYetPaid" name="MilestonePaymentsNotYetPaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_ShareBasedCompensationByShareBasedPaymentArrangementEquityInstrumentsOtherThanOptionsConvertedToUnvestedCommonStock" name="ShareBasedCompensationByShareBasedPaymentArrangementEquityInstrumentsOtherThanOptionsConvertedToUnvestedCommonStock" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_SummaryOfPerformanceStockUnitsActivity" name="SummaryOfPerformanceStockUnitsActivity" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_MilestoneAchievementMember" name="MilestoneAchievementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_UnamortizedStockBasedCompensationForStockOptions" name="UnamortizedStockBasedCompensationForStockOptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_CommonStockSharesIssuedAsAResultOfConversionOfTemporaryEquityIntoPermanentEquity" name="CommonStockSharesIssuedAsAResultOfConversionOfTemporaryEquityIntoPermanentEquity" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_PaymentOfMilestones" name="PaymentOfMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_ViractaLicenseAgreementMember" name="ViractaLicenseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AvailableForSaleSecuritie" name="AvailableForSaleSecuritie" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_SalesAgreementMember" name="SalesAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_FounderMember" name="FounderMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_PerformanceStockOptionsMember" name="PerformanceStockOptionsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_CommonStockToBeIssuedUnderTheEsppTableTextBlock" name="CommonStockToBeIssuedUnderTheEsppTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_UnvestedPsosAndPsusMember" name="UnvestedPsosAndPsusMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_ShareBasedCompensationByShareBasedPaymentArrangementEquityInstrumentsOtherThanOptionsOutstanding" name="ShareBasedCompensationByShareBasedPaymentArrangementEquityInstrumentsOtherThanOptionsOutstanding" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="dawn_SummaryOfPerformanceStockOptions" name="SummaryOfPerformanceStockOptions" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_BasisOfIssueDomain" name="BasisOfIssueDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_CommonSharesPurchaseAgreementMember" name="CommonSharesPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_PaymentOfAccruedInterest" name="PaymentOfAccruedInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="dawn_IncreaseDecreaseInAccruedExpensesAndOtherCurrentLiabilities" name="IncreaseDecreaseInAccruedExpensesAndOtherCurrentLiabilities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_UnvestedCommonSharesMember" name="UnvestedCommonSharesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_ConditionsForIssueAxis" name="ConditionsForIssueAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_ScheduleOfStockOptionsAssumptionsTableTextBlock" name="ScheduleOfStockOptionsAssumptionsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="dawn_SharesCommittedUnderESPPMember" name="SharesCommittedUnderESPPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_IncentiveSharePlanMemberMember" name="IncentiveSharePlanMemberMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_ResearchAndDevelopmentAgreementsMember" name="ResearchAndDevelopmentAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_DeferredSharesParValuePerShares" name="DeferredSharesParValuePerShares" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="dawn_AvailableForSaleSecuritieContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" name="AvailableForSaleSecuritieContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_SprintBioscienceAgreementMember" name="SprintBioscienceAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_PrepaidResearchAndDevelopmentExpenses" name="PrepaidResearchAndDevelopmentExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_AgreementAxis" name="AgreementAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="dawn_AvailableForSaleSecuritieContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" name="AvailableForSaleSecuritieContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="dawn_NumberOfEmployees" name="NumberOfEmployees" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="dawn_TemporaryEquityTextBlock" name="TemporaryEquityTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
